Intermediate Programming

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4/5/21, 10)50 PMIntermediate Programming
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Table of Contents
Objects
1. Learning Outcomes
2. Resources
2.1. Text
2.2. Videos
3. Introduction
4. Creating Objects
5. Diﬀerence between primitive type and reference type variables
6. Diﬀerence between Stack and Heap Memory
7. Passing Objects to Methods and Returning Objects from Methods
8. Key Terms
9. Exercises
9.1. Exercise 1
9.2. Exercise 2
9.3. Exercise 3
10. Issue Tracker/Comments
Object-Oriented Programming Design, Class Relationship, and Inheritance
1. Learning Outcomes
2. Resources
2.1. Text
2.2. Videos
3. Introduction
4. Object Oriented Program Design
4.1. Class Abstraction and Encapsulation
5. Class Relationship
5.1. Association
5.2. Aggregation
5.3. Composition
6. Inheritance
6.1. Overloading vs. Overriding
6.2. Accessibility Issue
7. Key Terms
8. Exercises
8.1. Exercise 1
8.2. Exercise 2
9. References
10. Issue Tracker/Comments
Polymorphism / Abstract Classes / Interfaces
1. Learning Outcomes

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2. Resources
2.1. Text
2.2. Videos
3. Introduction
4. Polymorphism through Inheritance
4.1. Dynamic Binding and Polymorphism
4.2. Why Polymorphism is Useful?
5. Abstract Class
5.1. Polymorphism through Abstract Class
5.2. An Experiment: Removing the Abstract Methods from the Super Class
6. Interface
6.1. A Class Can Implement Multiple Interfaces
6.2. Polymorphism through Interface
6.3. Interface Inheritance
7. Summary
8. Key Terms
9. Exercises
9.1. Exercise 1
9.2. Exercise 2
9.3. Exercise 3
Exceptions
1. Learning Outcomes
2. Resources
2.1. Text and Tutorials
2.2. Videos
3. Overview
4. Exception Handling
5. Checked Exception vs UnChecked Exception
6. Try/Catch/Finally Blocks
6.1. Declaring an exception
6.2. Throwing an exception
6.3. Catching an exception
7. Handling Exception vs Throwing Exception
8. Custom Exceptions
9. An example of Exception Handling used to validate input from user
10. Summary
11. Key Terms
12. Exercises
12.1. Exercise 1
12.2. Exercise 2

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12.3. Exercise 3
13. Issue Tracker/Comments
File Input/Output
1. Learning Outcomes
2. Resources
2.1. Text and Tutorials
2.2. Videos
3. Overview
4. Streams and Files
5. The File class
6. BuﬀeredReader and BuﬀeredWriter
6.1. An Example using BuﬀeredReader and BuﬀeredWriter
7. PrintWriter
7.1. Example of writing data to a text ﬁle
8. Scanner
8.1. How does Scanner work?
8.2. File reading Examples
9. Regular Expressions and parsing a ﬁle
10. Case Study: A Client Database
11. Key Terms
12. Exercises
12.1. Exercise 1
12.2. Exercise 2
12.3. Exercise 3
13. Issue Tracker/Comments
Generics
1. Learning Outcomes
2. Resources
2.1. Text
2.2. Videos
3. Introduction
4. Motivations and Beneﬁts
5. Deﬁning Generic Classes
5.1. Type Parameters/Type Variables
5.2. How to Use Generics?
5.3. Deﬁning Generic Interfaces
6. Generic Methods
6.1. The Bounded Generic Type
7. Raw Types and Backward Compatibility
8. Wildcard Generic Types

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9. Erasure
9.1. Class Type Erasure
9.2. Erasure of Generic Methods
10. Key Terms
11. Exercises
11.1. Exercise 1 (Palindrome)
11.2. Exercise 2
11.3. Exercise 3
11.4. Exercise 4
11.5. Exercise 5
12. References
13. Issue Tracker/Comments
Recursion
1. Learning Outcomes
2. Resources
2.1. Text and Tutorials
2.2. Videos
3. Introduction
4. Permutations and Combinations
5. Using Recursion in Mazes
6. Summary
7. Key Terms
8. Exercises
9. Issue Tracker/Comments
Basic Data Structures and Sorting
1. Learning Objectives
2. Resources
2.1. Text
3. Introduction
4. Lists
4.1. The Java List Interface
4.2. The ArrayList and LinkedList Classes
4.3. The List Iterator
4.4. Putting Things Together By Examples
4.5. Notes on Eﬃciency: Array List vs. Linked List
5. Stacks
5.1. The Stack Class
5.2. Applications of Stacks
5.3. A Classical Application: Checking for Balanced Parentheses
6. Queues

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6.1. The Queue Interface
6.2. Applications of Queues
7. Priority Queues
7.1. The PriorityQueue Class
7.2. The Comparator Interface
7.3. Applications of Priority Queues
8. Sorting
8.1. Naive Iterative Algorithms
8.2. Eﬃcient Algorithms
9. Exercises
9.1. Exercise 1
9.2. Exercise 2
9.3. Exercise 3
9.4. Exercise 4
9.5. Exercise 5
9.6. Exercise 6
9.7. Exercise 7
9.8. Exercise 8
9.9. Exercise 9
9.10. Exercise 10
10. Issue Tracker/Comments
Glossary

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1. Objects

1.1. Learning Outcomes

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1.2. Resources

1.2.1. Text

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1.2.2. Videos

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1.3. Introduction

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1.4. Creating Objects

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publicpublic classclass Square{

privateprivate doubledouble length;

publicpublic Square(){

length = 0.0;

}

publicpublic Square(doubledouble inLength){

length = inLength;

}

publicpublic voidvoid setLength(doubledouble inLength){

length = inLength;

}

publicpublic doubledouble getLength(){

returnreturn length;

}

publicpublic doubledouble computeArea(){

returnreturn length*length;

}

publicpublic doubledouble computePerimeter(){

returnreturn 4*length;

}

publicpublic String toString(){

String result = "square length: " + length + "\nperimeter: " + computePerimeter() + "\narea: " +

computeArea();

returnreturn result;

}

JAVA

publicpublic classclass SquareTester{

publicpublic staticstatic voidvoid main(String[] args){

Square square1 = newnew Square();

square1.setLength(10.5);

System.out.println(square1);

}

JAVA

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1.5. Diﬀerence between primitive type and reference type variables

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intint age1 = 40;

intint age2 = 18;

age1 = age2;

JAVA

4/5/21, 10)50 PMIntermediate Programming

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1.6. Diﬀerence between Stack and Heap Memory

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Square square1 = newnew Square(10.5);

Square square2 = newnew Square(5.2);

square1 = square2;

JAVA

4/5/21, 10)50 PMIntermediate Programming

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1.7. Passing Objects to Methods and Returning Objects from Methods

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8/(*(>#83/?-(83#(H*0%#(/G(H*+5*A0#(x(5&(83#(main()(>#83/?(?/#$(&/8(<3*&'#1(43#+#*$-(@3#&(*&(/AD#<8(5$(J*$$#?(*$

*&(*+'%>#&8(8/(*(>#83/?-(83#(H*0%#(/G(A/83(*88+5A%8#$(/G(/AD#<8(person1(*+#(<3*&'#?1

l#8%+&5&'(/AD#<8$(G+/>(>#83/?$-(*0$/(5&H/0H#$(+#8%+&5&'(83#(+#G#+#&<#(/G(83#(/AD#<81(;/($##(*&(#c*>J0#(/G(835$-(0#8m$

*??(*(&#@(>#83/?(8/(/%+(Square(<0*$$(<+#*8#?(*A/H#1(;35$(>#83/?(0//,$(*$($3/@&(A#0/@B

4/5/21, 10)50 PMIntermediate Programming

Page 14 of 185http://itec2150.gitlab.io/

;35$(>#83/?(<+#*8#$(*(&#@(/AD#<8(/G(<0*$$(Square(@583(length(H*0%#(/G(CTT(*&?(+#8%+&$(835$(&#@0"(<+#*8#?(/AD#<81

!#+#-(58(?/#$(&/8(*<8%*00"(+#8%+&(*(</J"(/G(83#(&#@0"(<+#*8#?(/AD#<8-(+*83#+(58(+#8%+&$(83#(+#G#+#&<#(/G(83#(&#@0"

<+#*8#?(/AD#<81(;/(8#$8(835$(&#@(>#83/?-(5&(83#(8#$8#+(>#83/?-(@#(@500(5&H/,#(83#(getSquare()(>#83/?(*$($3/@&

A#0/@B

;3#($8*8#>#&8(.d%*+#($d%*+#E(]($d%*+#C1'#8.d%*+#ORe(5&H/,#$(>#83/?(getSquare()(/&(+#G#+#&<#(H*+5*A0#

square11(;35$(<+#*8#$(*(&#@(/AD#<8(@583(length(CTT-(*$(?#G5&#?(5&(83#(getSquare()(>#83/?(*&?(*(+#G#+#&<#(8/(83*8

&#@(/AD#<8(5$(+#8%+&#?1(;35$(5$(?#J5<8#?(5&(83#(5>*'#(A#0/@B(

publicpublic Square getSquare(){

Square newSquare = newnew Square(100);

returnreturn newSquare;

}

JAVA

publicpublic classclass SquareTester{

publicpublic staticstatic voidvoid main(String[] args){

Square square1 = newnew Square();

square1.setLength(10.5);

System.out.println(square1);

Square square2 = square1.getSquare();

System.out.println(square2);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 15 of 185http://itec2150.gitlab.io/

;35$(+#8%+&#?(/AD#<8-(/+(+*83#+(+#G#+#&<#(5$(83#&(*$$5'&#?(8/(square21(;3#(+#$%08(/G(83*8(5$($3/@&(A#0/@1(

./-(@3#&(square2(5$(J+5&8#?-(83#(+#$%08$($3/%0?(A#(<*0<%0*8#?(*<</+5?&'(8/(CTT(*$(83#(0#&'83(/G(83#($d%*+#1(;3#$#

+#$%08$(/G(A/83(square1(*&?(square2(*+#($3/@&(A#0/@1(

1.8. Key Terms

`#3*H5/+B(*<85/&$(/G(*&(/AD#<8e(+#J+#$#&8#?(A"(83#(>#83/?$(/G(*&(/AD#<81

70*$$B(*(A0%#J+5&8(83*8(?#G5&#$(*&(/AD#<81

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UAD#<8P=&$8*&<#B(+#J+#$#&8$(*&(#&858"(5&(83#(+#*0(@/+0?(*&?(3*$($8*8#(*&?(A#3*H5/+1

UAD#<8Q/+5#&8#?(J+/'+*>>5&'B(*(@*"(/G(/+'*&5a5&'(</?#(*+/%&?(/AD#<8$-(5&$8#*?(/G(*<85/&$1

l#G#+#&<#B(>#>/+"(*??+#$$(/G(@3#+#(83#(/AD#<8(5$(0/<*8#?1

l#G#+#&<#(8"J#B(*(<0*$$e(H*+5*A0#(/G(835$(8"J#(<*&(+#G#+#&<#(*&(/AD#<8(/G(*(<0*$$1

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U%8(/+?#+1

4/5/21, 10)50 PMIntermediate Programming

Page 16 of 185http://itec2150.gitlab.io/

.8*8#B(+#J+#$#&8#?(A"(?*8*(G5#0?$(/+(*88+5A%8#$(/G(83#(/AD#<81

1.9. Exercises

1.9.1. Exercise 1

7+#*8#()#+$/&(*&?()#+$/&;#$8#+(<0*$$#$(8/(>/?#0(*(J#+$/&1(2#8*50$(*+#(*$(G/00/@$B

Tasks: Create business class Person

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*JJ+/J+5*8#(?*8*(8"J#$B

*1( &*>#(i($8/+#$(83#(G%00(&*>#(/G(*(J#+$/&

A1( *'#(i($8/+#$(*'#(/G(*(J#+$/&(5&(@3/0#("#*+$

<1( #"#7/0/+(i($8/+#$(83#(</0/+(/G(*(J#+$/&m$(#"#$

E1( 7+#*8#(*(&/Q*+'%>#&8(</&$8+%<8/+(G/+(835$(<0*$$

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K1( 7+#*8#('#88#+$P>%8*8/+$(G/+(#*<3(5&$8*&<#(H*+5*A0#

L1( 7+#*8#($#88#+$P*<<#$$/+$(G/+(#*<3(5&$8*&<#(H*+5*A0#

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83#(J#+$/&m$(&*>#1(=8(?/#$(&/8(&##?(*&"(J*+*>#8#+$(*&?(?/#$(&/8(+#8%+&(*&"(H*0%#$1

Tasks: Create tester class PersonTester

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E1( .U)(J#+$/&C(?#8*50$(%$5&'(8/.8+5&'OR1

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L1( b&$%+#(83*8(*00(/G("/%+(</?#(5$(83/+/%'30"(</>>#&8#?1

1.9.2. Exercise 2

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2#8*50$(*+#(*$(G/00/@$B

Bike Class

C1( 7+#*8#(*(A%$5&#$$(<0*$$(<*00#?(`5,#

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83#(J+/'+*>>#+m$(?5$<+#85/&1

4/5/21, 10)50 PMIntermediate Programming

Page 17 of 185http://itec2150.gitlab.io/

I1( F(&/Q*+'(</&$8+%<8/+(@583(H*0%#$(/G(E(G/+(&%>A#+(/G(@3##0$(8/(E-(f.<3@5&&g(G/+(>*&%G*<8%+#+-(*&?(ETCK(G/+

"#*+($3/%0?(#A(<+#*8#?1

K1( U83#+(</&$8+%<8/+$-('#88#+$-($#88#+$(*&?(8/.8+5&'OR(>#83/?($3/%0?(A#(<+#*8#?1

BikeTester Class

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83/$#(/G("/%+(<3/5<#1

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L1( F??(A5,#C(*&?(A5,#E(8/(835$(05$8

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^1( b&$%+#(83*8(*00(/G("/%+(</?#(5$(83/+/%'30"(</>>#&8#?1

1.9.3. Exercise 3

7+#*8#(<0*$$#$(8/(>/?#0(*&?(8#$8(8#c8A//,$1(V/00/@(83#(5&$8+%<85/&$($3/@&(A#0/@B

C1( 7+#*8#(*(A%$5&#$$(<0*$$(8/(>/?#0(*(8#c8A//,1(2#<5?#(@3*8(?*8*($3/%0?(A#($8/+#?(G/+(*(8#c8A//,(*&?(<+#*8#(*8

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I1( 7/>>#&8("/%+(</?#(83/+/%'30"1

1.10. Issue Tracker/Comments

=$$%#(;+*<,#+ O388J$BPP'583%A1</>P3J*+,WP3#0JY?#$,P5$$%#$R

4/5/21, 10)50 PMIntermediate Programming

Page 18 of 185http://itec2150.gitlab.io/

2. Object-Oriented Programming Design, Class Relationship, and

Inheritance

2.1. Learning Outcomes

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2.2. Resources

2.2.1. Text

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S*"G5#0?

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2.2.2. Videos

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b&<*J$%0*85/&(5&(6*H* O388J$BPP@@@1"/%8%A#1</>P@*8<3\H]<Z^K./LK<+[R

2.3. Introduction

4/5/21, 10)50 PMIntermediate Programming

Page 19 of 185http://itec2150.gitlab.io/

V+/>(J+#H5/%$(<3*J8#+$(*&?(/J#&($/%+<#(8#c8A//, O388JBPP58#<ECKT1??&$1&#8PR-("/%(0#*+&#?(3/@(8/(?#G5&#(<0*$$#$(G/+

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2.4. Object Oriented Program Design

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2.4.1. Class Abstraction and Encapsulation

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&#c8(<3*J8#+1

b&<*J$%0*85/&(Q(rClass encapsulation and abstraction are two sides of the same coinr(ON5*&'-(ETC[-

=&8+/?%<85/&(8/(6*H*B()+/'+*>>5&'(*&?(2*8*(.8+%<8%+#R(=8(5$(*(J+/<#$$(/G(@+*JJ5&'(</?#(*&?(?*8*(8/'#83#+(5&(*

$5&'0#(%&581(`"(%$5&'(83#(</&<#J8(/G(*<<#$$#+(*&?(>/?5G5#+O#1'('#88#+(*&?($#88#+(>#83/?$R-("/%(<*&(+#*?(?*8*(/+

4/5/21, 10)50 PMIntermediate Programming

Page 20 of 185http://itec2150.gitlab.io/

/&0"(*<<#$$(?*8*1(=G("/%(+#*?(83#(Person(<0*$$-(58(3*$(8@/(J+5H*8#(?*8*B(name(*&?(countryOfOrigin1(`"(%$5&'

83#(getName()(*&?(setName()(>#83/?$-(5&(83#(Main(8#$8#+(<0*$$-("/%(<*&(<3*&'#(83#(name(A"(<*005&'

setName(String name)(*&?(*<<#$$(83#(name(A"(<*005&'(getName()1(!/@#H#+-(83#+#(5$(&/($#88#+(8/(>/?5G"(83#

</%&8"(/G(/+5'5&1(U&0"(getCountryOfOrigin()(>#83/?(5$(J+/H5?#?1(;3#+#G/+#-("/%(<*&&/8(>/?5G"(/+($#8(83#

H*0%#(5&(83#(countryOfOrigin(?*8*(>#>A#+1(b&<*J$%0*85/&(5$(8/(35?#(83#(?*8*-(5>J0#>#&8*85/&-(83#(<0*$$

O*A$8+*<8(<0*$$(/+(5&8#+G*<#("/%(@500(0#*+&(*G8#+(835$(<3*J8#+R-(?#$5'&(*&?(5&$8*&85*85/&1

2.5. Class Relationship

;/(?#$5'&(<0*$$#$-(F$$/<5*85/&-(F''+#'*85/&-(7/>J/$585/&-(*&?(=&3#+58*&<#(*+#(G/%+(J/5&8$(@#(%$#(8/(?5$<%$$(83#

+#0*85/&$35J$(*>/&'(<0*$$#$1

2.5.1. Association

rF$$/<5*85/&(5$(*('#&#+*0(A5&*+"(+#0*85/&$35J(83*8(?#$<+5A#$(*&(*<85H58"(A#8@##&(8@/(<0*$$#$1(V/+(#c*>J0#-(*($8%?#&8

8*,5&'(*(</%+$#(5$(*&(*$$/<5*85/&(A#8@##&(83#(Student(<0*$$(*&?(83#(Course(<0*$$1(F&?(*(G*<%08"(>#>A#+(8#*<35&'

*(</%+$#(5$(*&(*$$/<5*85/&(A#8@##&(Faculty(<0*$$(*&?(83#(Course(<0*$$1r(ON5*&'1(ETC[(Q(=&8+/?%<85/&(8/(6*H*R

bc*>J0#B(s(7/%+$#-(;#*<3#+(*&?(.8%?#&8B(U&#(/+(S/+#($8%?#&8$(<*&(*$$/<5*8#(@583(*($5&'0#(8#*<3#+(Ul(U&#($5&'0#

$8%?#&8(<*&(*$$/<5*8#(@583(/&#(/+(>/+#(8#*<3#+$1(F&?(A/83(/G(83#>(<*&(A#(<+#*8#?(*&?(?#0#8#?(5&?#J#&?#&80"1(./

@3#&(*(8#*<3#+(0#*H#$(83#($<3//0-(83#&(8#*<3#+(@500(A#(+#>/H#?(G+/>(83#(05$8(*&?(@#(?/(&/8(&##?(8/(?#0#8#(*&"

publicpublic classclass Person

{

privateprivate String name;

privateprivate String countryOfOrigin = "Germany";

publicpublic String getName()

{

returnreturn name;

}

publicpublic voidvoid setName(String name)

{

thisthis.name = name;

}

publicpublic String getCountryOfOrigin()

{

returnreturn countryOfOrigin;

}

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

Person person = newnew Person();

person.setName("Ludwig van Beethoven");

System.out.println(person.getName() + " was a " + person.getCountryOfOrigin() + " composer." );

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 21 of 185http://itec2150.gitlab.io/

$8%?#&8$1(F&?(@3#&(*($8%?#&8(0#*H#$(83#($<3//0-(*&"(8#*<3#+$(*+#(&/8(0#*H5&'1(V/00/@5&'(#c*>J0#($/%+<#(</?#(5$

$3/@5&'(3/@(8/(5>J0#>#&8(*$$/<5*85/&(%$5&'(83#(<0*$$#$(/G(Student-(Course-(*&?(Teacher1(V/+(#c*>J0#-

addstudent()(>#83/?(5&(83#(Course(<0*$$(*&?(addCourse()(>#83/?(5&(83#(Student(<0*$$($3/@$(3/@(83#

*$$/<5*85/&(+#0*85/&$35J(5$(5>J0#>#&8#?1

./>#(/G(83#(*$$/<5*85/&(+#0*85/&$35J(<*&(A#(<*8#'/+5a#?(*$(#583#+(F''+#'*85/&(/+(7/>J/$585/&1(.##(;35$(#c*>J0#

O388J$BPP@@@1'##,$G/+'##,$1/+'P*$$/<5*85/&Q</>J/$585/&Q*''+#'*85/&QD*H*PR

2.5.2. Aggregation

classclass Course

{

privateprivate String courseName;

privateprivate ArrayList<Student> enrollmentList = newnew ArrayList<Student>();

privateprivate Teacher teacher;

publicpublic voidvoid addStudent(Student student)

{

enrollmentList.add(student);

}

classclass Student {

privateprivate ArrayList<Course> registeredCourse;

privateprivate String studentName;

publicpublic voidvoid addCourse(Course course)

{

}

classclass Teacher

{

privateprivate ArrayList<Course> teachingCourse;

publicpublic voidvoid addCourse(Course c)

{

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 22 of 185http://itec2150.gitlab.io/

;35$(+#0*85/&$35J(5$(r3*$Q*r(+#0*85/&$35J(A#8@##&(8@/(/AD#<8$1(=8(5$(>/+#($J#<5*05a#?(+#0*85/&$35J(/G(83#(*$$/<5*85/&

+#0*85/&$35J1(;3#(/@&#+(/AD#<8(5$(<*00#?(*&(*''+#'*85&'(/AD#<8(*&?(58$(<0*$$(5$(<*00#?(*''+#'*85&'(<0*$$1(7350?(/AD#<8

/+($%AD#<8(/AD#<8(5$(<*00#?(*''+#'*8#?(/AD#<8(*&?(58$(<0*$$(5$(<*00#?(*''+#'*8#?(<0*$$1

bc*>J0#$B(Student(<0*$$(*&?(Address(<0*$$1(.8%?#&8(<0*$$(<*&(3*H#(+#G#+#&<#(/G(F??+#$$(<0*$$(A%8(F??+#$$(<0*$$

?/#$(&/8(3*H#(83#(+#G#+#&<#(/G(.8%?#&8(<0*$$1(=8(?/#$(&/8(5&H/0H#(/@&5&'($/(*??+#$$(?/#$(&/8(&##?(8/(A#(85#?(8/(*

$8%?#&81(F&(address can exist by itself1

Employee(<0*$$(>*"(3*H#(G5#0?$(id, name, email, phone-(#8<1(F&?(*0$/(</&8*5&$(*&(/AD#<8(&*>#?(address1(N#8m$

$%JJ/$#(835$(*??+#$$(3*$(G5#0?$(city, state, zipcode-(#8<1(=&(835$(<*$#-(Employee(3*$(*&(address($/(83#(+#0*85/&$35J

5$(rb>J0/"##(Has-A(*??+#$$1r(O.##(A#0/@R

2.5.3. Composition

;35$(+#0*85/&$35J(5$(*0$/(3*$Q*(+#0*85/&$35J(@3#&(*(<0*$$(3*$(83#(/@&#+$35J(/G(*&/83#+($%AD#<8(<0*$$(A%8(83#($%AD#<8

depends on(83#(/@&#+(<0*$$1(=G(83#(#c5$8#&<#(/G(83#(*''+#'*8#?(/AD#<8(5$(?#J#&?#&8(/&(83#(*''+#'*85&'(/AD#<8-(83#&

83#(+#0*85/&$35J(5$(</>J/$585/&1(7/>J/$585/&(5$(83#($8+/&'#$8(G/+>(/G(*$$/<5*85/&(*&?(*''+#'*85/&(5$(@#*,#+

+#0*85/&$35J(@350#(F''+#'*85/&(*&?(7/>J/$585/&(*+#(H#+"($5>50*+1(V/+(#c*>J0#-(J0#*$#(8*,#(*(0//,(*8(83#(G/00/@5&'

J+/'+*>$-(Person(*&?(Job1(;3#(Person(3*$(*(D/A(5&$8*&<#(H*+5*A0#($/(@#(<*&(<+#*8#(*(Job(<0*$$1(=8(3*$(r*(person

3*$(*(jobr(+#0*85/&$35J1

classclass Employee

{

intint id;

String name;

Address address;

//Address is a class

}

JAVA

publicpublic classclass Person

{

//composition has-a relationship

privateprivate Job job;

publicpublic Person()

{

thisthis.job=newnew Job();

job.setSalary(1000L);

}

publicpublic longlong getSalary()

{

returnreturn job.getSalary();

}

publicpublic classclass Job

{

privateprivate String position;

privateprivate longlong salary;

privateprivate intint id;

publicpublic String getRole()

{

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 23 of 185http://itec2150.gitlab.io/

;3/+>A#&(6*&$$#&(#cJ0*5&$(*A/%8(83#(</>J/$585/&(</&&#<85&'(8/(83#(+#*0(@/+0?(5&<0%?5&'(A#&#G58$(@583(>/+#

#c*>J0#$ O388J$BPP$8*<,5G"1</>P//JQ</&<#J8$Q</>J/$585/&PR1

2.6. Inheritance

=&3#+58*&<#(5$(*(J/@#+G%0(>#<3*&5$>(83*8(*00/@$("/%(8/(?#G5&#(&#@(<0*$$#$(G+/>(*&(#c5$85&'(<0*$$1(;3#(#c5$85&'

<0*$$(5$(*(>/+#('#&#+*0(<0*$$-(<*00#?(*($%J#+<0*$$1(F($%J#+<0*$$(5$(*0$/(+#G#++#?(8/(*$(*(J*+#&8(<0*$$(/+(*(A*$#(<0*$$1

;3#(6*H*(5&3#+58*&<#(*00/@$(*(6*H*(<0*$$(8/(5&3#+58(G+/>(*($5&'0#($%J#+<0*$$1(U&0"($5&'%0*+(5&3#+58*&<#(5$(*00/@#?1

;3#(&#@(<0*$$#$(*+#($J#<5*05a#?(<*$#$(/G(83#($%J#+<0*$$1(;3#"(*+#(<*00#?($%A<0*$$#$(/G(83*8($%J#+(<0*$$1(F($%A<0*$$

*%8/>*85<*00"(5&3#+58$(*00(83#(5&$8*&<#(H*+5*A0#$(>#83/?$(G+/>(58$($%J#+<0*$$1(=8(>*"(?#G5&#(58$(/@&(&#@(H*+5*A0#$

*&?(>#83/?$1(=8(>*"(*0$/(/H#++5?#(*&"(5&3#+58#?(>#83/?$1(=8(>#*&$(83*8(83#(>#83/?(3*$(83#($*>#(>#83/?

$5'&*8%+#(5&(A/83(83#($%J#+<0*$$(*&?($%A<0*$$1(=8(>#*&$(8/(J+/H5?#(*(&#@(5>J0#>#&8*85/&(G/+(83*8(>#83/?(5&(83#

$%A<0*$$1

returnreturn position;

}

publicpublic voidvoid setRole(String position)

{

thisthis.position = position;

}

publicpublic longlong getSalary()

{

returnreturn salary;

}

publicpublic voidvoid setSalary(longlong salary)

{

thisthis.salary = salary;

}

publicpublic intint getId()

{

returnreturn id;

}

publicpublic voidvoid setId(intint id)

{

thisthis.id = id;

}

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

Person john = newnew Person();

longlong salary = john.getSalary();

System.out.println("John's Salary is " + salary);

}

4/5/21, 10)50 PMIntermediate Programming

Page 24 of 185http://itec2150.gitlab.io/

;3#($%A<0*$$(*&?(58$($%J#+<0*$$(G/+>(*(is-a(+#0*85/&$35J1(.##(83#(?5*'+*>(/G(*($%J#+<0*$$(<*00#?(Vehicle(*&?(8@/

$%A<0*$$#$(<*00#?(Car(*&?(Truck-(Car(5$(*(Vehicle(*&?(Truck(5$(*(Vehicle1(=&(/83#+(@/+?$-(Car(<0*$$(5&3#+58$(*00

*<<#$$5A0#(?*8*(G5#0?$(*&?(>#83/?$(G+/>(83#(Vehicle(<0*$$(*&?(83#(;+%<,(<0*$$(5&3#+58$(*00(*<<#$$5A0#(?*8*(G5#0?$(*&?

>#83/?$(G+/>(83#(Vehicle(<0*$$1(=&(ZSN-(*&(*++/@(J/5&8$(G+/>(*($%A<0*$$(8/(58$($%J#+<0*$$1

F<</+?5&'(8/(2*H5?(F1(;*"0/+(5&(35$(A//,(UAD#<8QU+5#&8#?(;#<3&/0/'"-(3#(>#&85/&#?(83*8(83#(/AD#<8Q/+5#&8#?

*JJ+/*<3(5$(>/+#(&*8%*01(V/+(#c*>J0#-r83#(A*$5<(A%50?5&'(A0/<,(/%8(/G(@35<3(*00(05H5&'(835&'$(*+#(</>J/$#?(5$(83#

<#001(7#00$(*+#(/+'*&5<(J*<,*'#(83*8-(05,#(/AD#<8$-(</>A5&#(+#0*8#?(5&G/+>*85/&(*&?(A#3*H5/+1(S/$8(/G(83#

5&G/+>*85/&(5$(</&8*5&#?(5&(J+/8#5&(>/0#<%0#$(@5835&(83#(&%<0#%$(/G(83#(<#001(;3#(A#3*H5/+-(@35<3(>*"(+*&'#(G+/>

#&#+'"(</&H#+$5/&(8/(>/H#>#&8-(5$(<*++5#?(/%8(A"($8+%<8%+#(/%8$5?#(83#(&%<0#%$1g(!#(*0$/(#cJ0*5&#?(*A/%8(83#

35#+*+<3"(/G(<#00(8"J#$(*$("/%($##(83#(5&3#+585&'(<#00(?5*'+*>1(r;3#(<#00(5$(8+%0"(%&5H#+$*0(A%50?5&'(A0/<,1(F00(<#00$

$3*+#(*(</>>/&($8+%<8%+#(*&?(/J#+*8#(*<</+?5&'(8/(83#($*>#(A*$5<(J+5&<5J0#$1(45835&(835$(A*$5<($8+%<8%+#-(J0*&8

<#00$(3*H#(*(3*+?(/%8#+(@*00(8/(>*,#(83#>(+5?'5?-(A0//?(<#00$(*+#(>/A50#(*&?($J#<5*05a#?(8/(8+*&$J/+8('*$#$-(>%$<0#

<#00$(*+#(*A0#(8/(?5$8/+8(83#5+($3*J#(8/(J#+G/+>(>#<3*&5<*0(@/+,1r

2.6.1. Overloading vs. Overriding

UH#+0/*?5&'(*(>#83/?(5$(8/(?#G5&#(>%085J0#(>#83/?$(@583(83#($*>#(&*>#(A%8(?5GG#+#&8($5'&*8%+#$1

4/5/21, 10)50 PMIntermediate Programming

Page 25 of 185http://itec2150.gitlab.io/

UH#++5?5&'(>#83/?$(5$(8/(J+/H5?#(*(&#@(5>J0#>#&8*85/&(G/+(*(>#83/?(5&(83#($%A<0*$$(O.##(#c*>J0#(>#83/?$

G+/>(ClassB(*&?(NamePointR1

=&(G/00/@5&'(?5*'+*>-(83#(ClassA(5$(83#($%J#+<0*$$(*&?(ClassB(5$(83#($%A<0*$$1

publicpublic classclass Addition

{

publicpublic intint add(intint a, intint b)

{

returnreturn a + b;

}

publicpublic intint add(intint a, intint b, intint c)

{

returnreturn a + b + c;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 26 of 185http://itec2150.gitlab.io/

=&(G/00/@5&'(?5*'+*>-(83#(ClassA(5$(83#($%J#+<0*$$(G/+(ClassC(*&?(ClassB(*&?(ClassC(5$(83#($%J#+<0*$$(G/+(ClassD1

/**

* Class: ClassA

publicpublic classclass ClassA {

protectedprotected intint m;

publicpublic String toString()

{

returnreturn newnew String("(" + m + ")");

}

/**

* Class: ClassB

publicpublic classclass ClassB extendsextends ClassA

{

privateprivate intint n;

publicpublic String toString()

{

returnreturn newnew String ("(" + m + "," + n + ")");

}

/**

* Class: Main

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

ClassA a = newnew ClassA();

System.out.println("a = " + a);

ClassB b = newnew ClassB();

System.out.println("b = " + b);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 27 of 185http://itec2150.gitlab.io/

N#8m$(8*,#(*(0//,(*8(;3#(Point(<0*$$(*&?(NamedPoint(<0*$$1(;3#(Point(<0*$$(3*$(8@/(J+5H*8#(5&$8*&<#(H*+5*A0#$(c

*&?("(*&?(58(5$(83#($%J#+<0*$$(/G(*($%A<0*$$(NamedPoint(<0*$$1(F$(*(+#$%08(/G(5&3#+58*&<#-(83#(NamedPoint(<0*$$

5&$8*&<#P/AD#<8(@500(3*H#(83+##(G5#0?$B(x(*&?(y(5&3#+58#?(G+/>(83#($%J#+<0*$$(Point(*&?(83#(.8+5&'(5&$8*&<#(H*+5*A0#

name(@35<3(5$(?#G5&#?(5&(83#(NamedPoint(<0*$$1

;3#(NamedPoint(<0*$$(3*$(*(8/8*0(G5H#(+#'%0*+(>#83/?$1(=8(5&3#+58$(83#(equals(), getX(), and getY()(>#83/?$(G+/>

83#($%J#+<0*$$(Point1(=8(<+#*8#$(*(&#@(>#83/?(getName()(*&?(/H#++5?#$(*&(#c5$85&'(>#83/?(toString()1(`#$5?#$

83#(G5H#(+#'%0*+(>#83/?$-(83#(NamedPoint(<0*$$(*0$/(</&8*5&$(*(</&$8+%<8/+(@583(83+##(J*+*>#8#+$B(x, y-(*&?

name1(;3#(</&$8+%<8/+(/G(83#(NamedPoint(5&H/,#$(83#(</&$8+%<8/+(/G(83#(Point($%J#+<0*$$(%$5&'(83#(,#"@/+?

$%J#+(A"(J*$$5&'(x(*&?(y1(=&3#+58*&<#(*JJ05#$(8/(<0*$$(G5#0?(x(*&?(y(*&?(>#83/?$(getX(), getY(), equals()-(A%8(&/8

</&$8+%<8/+$1(=8(5$(A#<*%$#(83#(</&$8+%<8/+(>%$8(*0@*"$(3*H#(83#($*>#(&*>#(*$(58$(<0*$$1(;3%$-($%A<0*$$#$(%$%*00"

#cJ05<580"(?#G5&#(83#5+(/@&(</&$8+%<8/+$1

publicpublic classclass Point

{

//objects represent lattice points in the cartesian plane

//object are immutable

protectedprotected doubledouble x, y;

// the point's coordinates. In this program, we used protected.

publicpublic Point(doubledouble x, doubledouble y){

thisthis.x = x;

thisthis.y = y;

}

publicpublic booleanboolean equals(Point p)

{

returnreturn (x == p.x && y == p.y);

}

publicpublic doubledouble getX()

{

returnreturn x;

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 28 of 185http://itec2150.gitlab.io/

}

publicpublic doubledouble getY()

{

returnreturn y;

}

publicpublic String toString()

{

returnreturn newnew String("(" + getX() + ", " + getY() + ")");

//why getX() and getY()?

}

/**

* this class to hold named location's information for data point (coordinates of x and y).

publicpublic classclass NamedPoint extendsextends Point

{

finalfinal privateprivate String name;

publicpublic NamedPoint(doubledouble x, doubledouble y, String name)

{

supersuper(x, y);

//super keyword is to invoke superclass' constructor. This statement super(x,y) invokes the Point class

constructor

//that matches the arguments and it must be the first statement of the subclass' constructor as you see

here.

//this is the way to explicitly invoke a superclass construtor.

thisthis.name = name;

}

publicpublic String getName()

{

returnreturn name;

}

@Override

publicpublic String toString()

{

returnreturn name + "(" + x + ", " + y + ")";

//why x and y?

}

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

NamedPoint p = newnew NamedPoint(0,0, "Origin (O)");

System.out.println("p: " + p);

System.out.println("P.getName(): " + p.getName());

System.out.println("p.getX(): " + p.getX());

//getX() method is inherited from the Point superclass.

NamedPoint q = newnew NamedPoint(1,10,"A");

System.out.println("q: " + q);

System.out.println("q.equals(p): " + q.equals(p));

//q is able to invoke the equals() method that it inherited from the superclass.

4/5/21, 10)50 PMIntermediate Programming

Page 29 of 185http://itec2150.gitlab.io/

2.6.2. Accessibility Issue

Table 1. Access Levels

Modifier Class Package Subclass World

J%A05< 9 9 9 9

J+/8#<8#? 9 9 9 j

&/(>/?5G5#+(/+

?#G*%08

9 9 j j

J+5H*8# 9 j j j

=G(83#(5&$8*&<#(H*+5*A0#$(5&(83#($%J#+(<0*$$(*+#(J+5H*8#-(83#($%A<0*$$(<*&&/8(?5+#<80"(*<<#$$(83#$#(H*+5*A0#$-(#H#&

83/%'3(83#"(*+#(5&3#+58#?1(;/(+#8+5#H#P%J?*8#(83#(H*0%#$(/G(83#$#(H*+5*A0#$-(83#('#88#+P$#88#+(>#83/?(/G(83#($%J#+

<0*$$(@500(&##?(8/(A#(%$#?1(;3#(G/00/@5&'(5$(*&(#c*>J0#1

}

// Testing if a subclass can access the private members of a superclass

classclass Vehicle

{

privateprivate String licensePlate;

publicpublic String getLicensePlate()

{

returnreturn licensePlate;

}

publicpublic voidvoid setLicensePlate(String licensePlate)

{

thisthis.licensePlate = licensePlate;

}

classclass Car extendsextends Vehicle

{

privateprivate intint numberOfSeat;

privateprivate intint manufacturedYear;

publicpublic intint getNumberOfSeat()

{

returnreturn numberOfSeat;

}

publicpublic voidvoid setNumberOfSeat(intint numberOfSeat)

{

thisthis.numberOfSeat = numberOfSeat;

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 30 of 185http://itec2150.gitlab.io/

2.7. Key Terms

F<<#$$($J#<5G5#+$B(J+5H*8#-(?#G*%08-(J+/8#<8#?-(*&?(J%A05<1

F$$/<5*85/&B(*('#&#+*0(A5&*+"(+#0*85/&(A#8@##&(8@/($#J*+*8#(<0*$$#$1(V/+(#c*>J0#-(*($8%?#&8(8*,5&'(*(</%+$#(5$(*&

*$$/<5*85/&(A#8@##&(83#(.8%?#&8(<0*$$(*&?(83#(7/%+$#(<0*$$1

F''+#'*85/&B(*&(*$$/<5*85/&(@3#&(/&#(/AD#<8(%$#$(*&/83#+(/AD#<81

7/>J/$585/&B(*&(*$$/<5*85/&(@3#&(/&#(/AD#<8(/@&$(/83#+(<0*$$(*&?(/83#+(<0*$$(<*&&/8(>#*&5&'G%00"(#c5$81

7/>J/$585/&(5$($8+/&'#+(83*&(*''+#'*85/&1

2#G*%08(*<<#$$($J#<5G5#+(O&/(>/?5G5#+RB(*<<#$$5A0#(@5835&(83#($*>#(J*<,*'#1

}

publicpublic intint getManufacturedYear()

{

returnreturn manufacturedYear;

}

publicpublic voidvoid setManufacturedYear(intint manufacturedYear)

{

thisthis.manufacturedYear = manufacturedYear;

}

@Override

publicpublic String toString()

{

returnreturn "Car\n" +

"Number of Seats: " + numberOfSeat + '\n' +

"Manufactured Year: " + manufacturedYear;

}

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

Vehicle vehicle = newnew Vehicle();

Car car = newnew Car();

//no error to set value because setLicensePlate() is public method of the Vehicle superclass

//but you cannot modify the value of licensePlate directly from the superclass - Vehicle

vehicle.setLicensePlate("UIO678");

car.setNumberOfSeat(7);

//no error to setNumberOfSeat because setNumberOfSeat() is a public method of

the Car class

car.setManufacturedYear(2020);

//no error to setManufacturedYear because setManufacturedYear() is a

public method of the Car class

System.out.println(car.toString());

}

4/5/21, 10)50 PMIntermediate Programming

Page 31 of 185http://itec2150.gitlab.io/

=&3#+58*&<#B(*(>#<3*&5$>(8/(?#G5&#(&#@(<0*$$#$(G+/>(#c5$85&'(<0*$$#$1(=&(D*H*-(<0*$$#$(<*&(5&3#+58(83#(J+/J#+85#$

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2.8. Exercises

2.8.1. Exercise 1

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5&8/(83#(G5+$8(A0/<,(@3#+#(58(@/%0?(G581(9/%+(J+/'+*>($3/%0?(J+/>J8(83#(%$#+(8/(#&8#+(83#(>*c5>%>($5a#(/G(83#

?5+#<8/+"(F(O#1'1(43*8(5$(83#(>*c5>%>($5a#(/G(83#(?5+#<8/+"(F\rR-(*0$/(J+/>J8(83#(%$#+(8/(#&8#+(83#(&%>A#+(/G(G50#$

8/($8/+#-(*&?(83#&(J+/>J8(83#(%$#+(8/(#&8#+(#*<3(G50#($5a#(5&(_`1(;3#(J+/'+*>(@500(?5$J0*"(83#(8/8*0(&%>A#+(/G

A0/<,$(&##?#?(8/($8/+#(G50#$(*&?(G50#($5a#1(Z$#(83#($8*+8#+(</?#(J+/H5?#?(*$(G/00/@$(*&?(3#+#(5$(83#($*>J0#(+%&B

What is the maximum size of the directory A?

How many files do you have to store in directory A

Enter each file size in KB

4 5 10 2 7 9 5 23 11 8

Block 1 can store following size file(s)4 5 10 2 7 9 5 8 (in KB)

Block 2 can store following size file(s)23 11 (in KB)

Starter Code:

importimport java.util.ArrayListjava.util.ArrayList;

importimport java.util.Scannerjava.util.Scanner;

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 32 of 185http://itec2150.gitlab.io/

2.8.2. Exercise 2

9/%+(8*$,(5$(8/(?#H#0/J(*(J+/'+*>(8/(?5$J0*"(+#<5J#$(/G(?5GG#+#&8(8"J#$(/G(A+#*?O#1'1($/%+?/%'3(A+#*?-(>%GG5&$-

J*$8+5#$-(#8<R

Scanner input = newnew Scanner(System.in);

//complete here

}

publicpublic staticstatic ArrayList<Storage> firstFit(intint[] fileSizeList, intint maxFileSize)

{

//Complete here

}

importimport java.util.ArrayListjava.util.ArrayList;

publicpublic classclass Storage

{

privateprivate ArrayList<Integer> file = newnew ArrayList<>();

privateprivate intint maxFileSize = 0;

privateprivate intint totalSize = 0;

publicpublic Storage(intint maxFileSize)

{

//complete here

}

/**

* method addFile

* @param fileSize

* @return boolean

* description: this method will add file as long as total size

* includng a new file size you want to add

* is not larger than the maximum file size

publicpublic booleanboolean addFile(intint fileSize)

{

//complete here

}

publicpublic intint getNumberOfFiles()

{

returnreturn file.size();

}

@Override

publicpublic String toString()

{

//complete here

}

4/5/21, 10)50 PMIntermediate Programming

Page 33 of 185http://itec2150.gitlab.io/

Directions are as follows.

▪Create Bread superclass that has default constructor with general ingredients and recipe.

It also has a constructor with all the parameters. Bread also comes with getter, setter, and toString methods.

Besides those methods, the Bread superclass has the bake method to change the state of bread from "not baked" to

"baked",

unless it is already "baked."

And also has getIngredients method.

This method returns a String of all the ingredients of the instance. And you can add other methods as you want.

There are five subclasses of Bread class. Each of them will have unique properties with unique ingredients.

–Instance variables: flour, water, salt, sugar, baking powder, yeast, breadName, state, recipe.

–Default constructor

–Constructor with all parameters.

–Getters, setters, toString method.

–bake, getIngredients, and other methods you want to include.

▪Create SourdoughBread subclass

–Instance variables: you will need to create unique instance variables for sourdough bread.

–Constructors, getters, setters, recipe method to describe how to, and toString or you can add other methods

you want to include.

▪Create Pastry subclass

–Instance variables: you will need to create unique instance variables for pastry.

–Constructors, getters, setters, recipe method to describe how to, and toString or you can add other methods

you want to include

▪Create three more different type of bread subclasses (e.g. SourdoughBread- see follow sample)

–Constructors, getters, setters, recipe method to describe how to, and toString or you can add other methods

you want to include

▪Main class. This class has an instance of Bread and its subclasses. This program will display recipes of all

classes and methods.

▪ReadMe.txt – this file will explain about your program in details.

A part of the sample run is as follows:

SourdoughBread class testing

Ingredients of Sourdough Bread are:

5.00 cups of flour

1.50 cups of water

2.50 tsps of salt

1.00 tsp of yeast

1.00 cup of ripe sourdough starter

A recipe of Sourdough Bread:

1. Mix flour, water, salt, baking powder, yeast, and ripe sourdough starter.

2. Make the dough

3. Bulk Rise

4. Stretch and fold the dough

5. Cut and shape the dough

6. Second rise

6. Preheat the oven to 450°F towards the tail end of the second rise.

7. Spray the laof with luke warm water.

8. Bake the bread at 400°F for 20 minutes, until deep golden brown.

9. Remove the bread from the oven.

10.Let the bread cool until good to eat.

Can't bake, Sourdough Bread is already baked.

The Sourdough Bread is baked now.

4/5/21, 10)50 PMIntermediate Programming

Page 34 of 185http://itec2150.gitlab.io/

2.9. References

N5*&'-(21(OETC[R1(=&8+/?%<85/&(8/(6*H*B()+/'+*>>5&'(*&?(2*8*(.8+%<8%+#$(OCC83(#?1R1()#*+$/&(;*"0/+-(21F1(OC^[CR1

UAD#<8QU+5#&8#?(;#<3&/0/'"B(F(S*&*'#+m$(q%5?#1.#+H5/

2.10. Issue Tracker/Comments

=$$%#(;+*<,#+ O388J$BPP'583%A1</>P3J*+,WP3#0JY?#$,P5$$%#$R

4/5/21, 10)50 PMIntermediate Programming

Page 35 of 185http://itec2150.gitlab.io/

3. Polymorphism / Abstract Classes / Interfaces

3.1. Learning Outcomes

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3.2. Resources

3.2.1. Text

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4/5/21, 10)50 PMIntermediate Programming

Page 36 of 185http://itec2150.gitlab.io/

FA$8+*<8(70*$$#$(*&?(S#83/?$ O388J$BPP@@@1@I$<3//0$1</>PD*H*PD*H*Y*A$8+*<81*$JR

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3.2.2. Videos

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3.3. Introduction

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4/5/21, 10)50 PMIntermediate Programming

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G/+(83#($%J#+(<0*$$(Character-(83#+#(5$(+#*00"(&/(>#*&5&'G%0(5>J0#>#&8*85/&(G/+(83#(walk(>#83/?1(4#(</%0?(>*,#

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5&8#+G*<#(A"(J+/H5?5&'(?#G5&585/&$(G/+(83#(*A$8+*<8(>#83/?$(</&8*5&#?(5&(83#(5&8#+G*<#1(F(H*+5*A0#(/G(*&(5&8#+G*<#

8"J#(<*&(A#(%$#?(8/(3/0?(+#G#+#&<#$(8/(/AD#<8$(/G(*&"(<0*$$#$(83*8(5>J0#>#&8(83#(5&8#+G*<#1(;35$(*00/@$(#H#&(>/+#

G0#c5A0#(J/0">/+J35$>(83*&(83*8(5$(#&*A0#?(A"(83#(5&3#+58*&<#(+#0*85/&$35J$1

3.4. Polymorphism through Inheritance

=&(835$($#<85/&-(@#(@500(G5+$8(0#*+&(@3*8(5$(?"&*>5<(A5&?5&'(*&?(J/0">/+J35$>(*&?(83#&(%&?#+$8*&?(@3"

J/0">/+J35$>(5$(*(J/@#+G%0(8//0(8/(>*,#(58(#*$"(8/(>*&*'#(/AD#<8$(A#0/&'5&'(8/(?5GG#+#&8(<0*$$#$1

3.4.1. Dynamic Binding and Polymorphism

b*<3(/G(%$(<*&(*$$%>#(?5GG#+#&8(5?#&8585#$1(V/+(#c*>J0#-(@#(*+#(*00(>#>A#+$(/G(83#(qq7(</>>%&58"-(@350#($/>#(/G

%$(A#0/&'(8/(83#(#>J0/"##(<*8#'/+"(*&?(83#(/83#+$(A#0/&'(8/(83#($8%?#&8(<*8#'/+"1(b>J0/"##$(*+#(G%+83#+(?5H5?#?

5&8/(83#($8*GG(<*8#'/+"(*&?(83#(G*<%08"(<*8#'/+"1(=G(@#(%$#(*(6*H*(<0*$$(8/(<*J8%+#(#*<3(<*8#'/+"-(83#(G/00/@5&'(ZSN

<*J8%+#$(83#(+#0*85/&$35J(*>/&'(83#$#(<0*$$#$1

;3#(G/00/@5&'(*+#(?#G5&585/&$(G/+(83#$#(<0*$$#$1

Example 1: GGCMember.java

4/5/21, 10)50 PMIntermediate Programming

Page 38 of 185http://itec2150.gitlab.io/

Example 1: Employee.java

Example 1: Faculty.java

publicpublic classclass GGCMember

{

privateprivate longlong id;

privateprivate String firstName;

privateprivate String lastName;

publicpublic GGCMember(longlong id, String firstName, String lastName)

{

thisthis.id = id;

thisthis.firstName = firstName;

thisthis.lastName = lastName;

}

//getters and setters for ID, firstName and lastName (not shown)

@Override

publicpublic String toString()

{

returnreturn "GGCMember [ID=" + id + ", " + firstName + " " + lastName + "]";

}

JAVA

publicpublic classclass Employee extendsextends GGCMember

{

privateprivate String division;

publicpublic Employee(longlong id, String firstName, String lastName, String division)

{

supersuper(id, firstName, lastName);

thisthis.division = division;

}

//getter and setter for division (not shown)

@Override

publicpublic String toString()

{

returnreturn "Employee [ID=" + supersuper.getID() + ", division=" + division +

", " + supersuper.getFirstName() + " " + supersuper.getLastName() + "]";

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 39 of 185http://itec2150.gitlab.io/

Example 1: Staff.java

Example 1: Student.java

publicpublic classclass Faculty extendsextends Employee

{

privateprivate String dept;

publicpublic Faculty(longlong id, String firstName, String lastName, String division, String dept)

{

supersuper(id, firstName, lastName, division);

thisthis.dept = dept;

}

//getter and setter for dept (not shown)

@Override

publicpublic String toString()

{

returnreturn "Faculty [division=" + supersuper.getDivision() + ", dept=" + dept + ", " + supersuper.getFirstName() +

" " + supersuper.getLastName() + "]";

}

JAVA

publicpublic classclass Staff extendsextends Employee

{

privateprivate String office;

publicpublic Staff(longlong id, String firstName, String lastName, String division, String office)

{

supersuper(id, firstName, lastName, division);

thisthis.office = office;

}

//getter and setter for office (not shown)

@Override

publicpublic String toString()

{

returnreturn "Staff [division=" + supersuper.getDivision() + ", office=" + office + ", " + supersuper.getFirstName()

+ " " + supersuper.getLastName() + "]";

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 40 of 185http://itec2150.gitlab.io/

6%$8(05,#(*($8%?#&8(5$(*0$/(*(qq7(>#>A#+-(*(.8%?#&8(/AD#<8(<*&(*0$/(A#(r<*00#?r(qq7S#>A#+(*&?(58$(+#G#+#&<#(<*&

A#($8/+#?(5&(*(qq7S#>A#+(H*+5*A0#1(.5>50*+0"-(*(V*<%08"(/+(.8*GG(/AD#<8(<*&(A#(r<*00#?r(b>J0/"##(/+(qq7S#>A#+

*&?(58$(+#G#+#&<#(<*&(A#($8/+#?(5&(#583#+(*&(b>J0/"##(H*+5*A0#(/+(*(qq7S#>A#+(H*+5*A0#1(;3*8(5$-(*&(/AD#<8(<*&(A#

*<<#$$#?(H5*(+#G#+#&<#(H*+5*A0#(/G(58$(8"J#(/+(*(+#G#+#&<#(H*+5*A0#(/G(*&"(/G(58$($%J#+<0*$$(8"J#O$R1(;35$('5H#$(%$(83#

G+##?/>(8/(%$#(/&#(H*+5*A0#(8/(3/0?(+#G#+#&<#$(8/(*&"(/AD#<8(/G(58$($%A<0*$$#$1(;3#(G/00/@5&'(5$(*&(#c*>J0#1

h*+5*A0#(m(5$(/G(83#(qq7S#>A#+(8"J#-(58(<*&(3/0?(+#G#+#&<#$(G/+(.8%?#&8(/AD#<8$-(.8*GG(/AD#<8$(*&?(V*<%08"(/AD#<8$1

Example 1: GGCRoster.java

h*+5*A0#(m(5$(*(qq7S#>A#+(H*+5*A0#1(43#&(05&#(L(5$(#c#<%8#?-(83#(+#G#+#&<#(G/+(*(.8%?#&8(/AD#<8(5$(*$$5'&#?(8/(m1

F8(835$(J/5&8-(m(3/0?$(*(+#G#+#&<#(8/(*(.8%?#&8(/AD#<81(;3#(</>J50#+(*00/@$(83#(*$$5'&>#&8(/G(*(.8%?#&8(/AD#<8(8/(*

qq7S#>A#+(H*+5*A0#-(A#<*%$#(.8%?#&8(5$(*($%A<0*$$(/G(qq7S#>A#+1(U&(05&#([-(m.toString()(5$(5>J05<580"(5&H/,#?1

;3#(?#<5$5/&(/&(@35<3(8/.8+5&'(>#83/?(8/(5&H/,#(5$(?#8#+>5&#?(@3#&(05&#([(5$(#c#<%8#?(O+%&(85>#R1(.5&<#(m(3/0?$(*

publicpublic classclass Student extendsextends GGCMember

{

privateprivate String major;

publicpublic Student(longlong id, String firstName, String lastName, String major) {

supersuper(id, firstName, lastName);

thisthis.major = major;

}

//getter and setter for major (not shown)

@Override

publicpublic String toString()

{

returnreturn "Student [ID=" + supersuper.getID() + ", major=" + major +

", " + supersuper.getFirstName() + " " + supersuper.getLastName() + "]";

}

JAVA

1| publicpublic classclass GGCRoster

2| {

3| publicpublic staticstatic voidvoid main(String[] args)

4| {

5| GGCMember m;

7| m = newnew Student(90011022L, "John", "Smith", "MATH");

//m is bound to a Student object

8| System.out.println(m);

//toString method for the Student object will be invoked

10| m = newnew Staff(90003088L, "Rachel", "Morgan", "Academic Affairs", "SST");

//m is bound to a Staff object

11| System.out.println(m);

//toString method for the Staff object will be invoked

12|

13| m = newnew Faculty(90021028L, "Linda", "Davis", "Academic Affairs", "CHEM");

//m is bound to a Faculty

object

14| System.out.println(m);

//toString method for the Faculty object will be invoked

15| }

16| }

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 41 of 185http://itec2150.gitlab.io/

+#G#+#&<#(8/(*(.8%?#&8(/AD#<8-(83#(8/.8+5&'(>#83/?(?#G5&#?(5&(83#(.8%?#&8(<0*$$(5$(5&H/,#?1(;35$(5$(<*00#?(dynamic

binding1(=8(>#*&$(83*8(83#(>#83/?(<*00(5$(A/&?#?(8/(83#(>#83/?(A/?"(*8(+%&85>#(5&$8#*?(/G(</>J50#(85>#1(;35$(5$

*0$/(,&/@&(*$(late binding1

U&(05&#(CC-(m('#8$(83#(+#G#+#&<#(8/(*(.8*GG(/AD#<8-($/(@3#&(05&#(CC(5$(#c#<%8#?(*&?(m.toString()(5$(5>J05<580"

5&H/,#?-(83#(8/.8+5&'(>#83/?(?#G5&#?(5&(83#(.8*GG(<0*$$(5$(5&H/,#?1

U&(05&#(CK-(m('#8$(83#(+#G#+#&<#(8/(*(V*<%08"(/AD#<8-($/(@3#&(05&#(CK(5$(#c#<%8#?(*&?(m.toString()(5$(5>J05<580"

5&H/,#?-(83#(8/.8+5&'(>#83/?(?#G5&#?(5&(83#(V*<%08"(<0*$$(5$(5&H/,#?1

4#(<*&(835&,(/G(H*+5*A0#(m(*$(8*,5&'(/&(?5GG#+#&8(G/+>$-($/>#85>#$(+#G#++5&'(8/(*(.8%?#&8(/AD#<8-($/>#85>#$

V*<%08"-(*&?($/>#85>#$(.8*GG1(4#(<*00(58(polymorphism-(@35<3(>#*&$(83*8(*(+#G#+#&<#(H*+5*A0#(<*&(3/0?

+#G#+#&<#$(8/(?5GG#+#&8(8"J#$(/G(/AD#<8$1(V/+(#c*>J0#-(*(+#G#+#&<#(H*+5*A0#(</%0?(+#G#+(8/(/AD#<8$(83*8(A#0/&'(8/(*&"

/G(58$($%AQ<0*$$#$1(4#(@500(0#*+&(0*8#+(5&(835$(<3*J8#+-(83*8(*(+#G#+#&<#(H*+5*A0#(<*&(*0$/(3/0?(+#G#+#&<#$(8/(/AD#<8$

A#0/&'5&'(8/(?5GG#+#&8(<0*$$#$(83*8(5>J0#>#&8(83#($*>#(5&8#+G*<#1

;3#(G/00/@5&'(5$(83#(/%8J%8(/G(83#(J+/'+*>1

3.4.2. Why Polymorphism is Useful?

9/%(>5'38(A#(@/&?#+5&'(@3"(@#(&##?(J/0">/+J35$>1(9/%(>5'38($*"(83*8("/%(</%0?(@+58#(*(J+/'+*>(O05,#(83#(/&#

A#0/@R(83*8(?/#$(83#($*>#(835&'(*$(83#(#c*>J0#(*A/H#(@583/%8(%$5&'(J/0">/+J35$>1

Example 1: GGCRosterNoPolymorphism.java

)/0">/+J35$>(@500(>*,#(J+/'+*>>5&'(</&H#&5#&8(5G("/%+(J+/'+*>(&##?$(8/(J+/<#$$(*($#8(/G(?5GG#+#&8(A%8(+#0*8#?

/AD#<8$($"$8#>*85<*00"-(/G8#&(5&(0//J$1(;3#(G/00/@5&'(5$($%<3(*&(#c*>J0#1

Example 1: GGCRosterLoop.java

Student [ID=90011022, major=MATH, John Smith]

Staff [division=Academic Affairs, office=SST, Rachel Morgan]

Faculty [division=Academic Affairs, dept=CHEM, Linda Davis]

publicpublic classclass GGCRosterNoPolymorphism

{

publicpublic staticstatic voidvoid main(String[] args)

{

Student m1 = newnew Student(90011022L, "John", "Smith", "MATH");

System.out.println(m1);

Staff m2 = newnew Staff(90003088L, "Rachel", "Morgan", "Academic Affairs", "SST");

System.out.println(m2);

Faculty m3 = newnew Faculty(90021028L, "Linda", "Davis", "Academic Affairs", "CHEM");

System.out.println(m3);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 42 of 185http://itec2150.gitlab.io/

=G("/%+(J+/'+*>(&##?$(8/(J+/<#$$(*(>5c8%+#(/G(.8%?#&8-(.8*GG(*&?(V*<%08"(/AD#<8$-("/%(<*&(%$#(*&(*++*"(/G

qq7S#>A#+(O83#5+(</>>/&($%J#+<0*$$R(8/($8/+#(83#>(O*$(/&(05&#(IR1(b*<3(*++*"(#0#>#&8(O*&(5&?#c#?(H*+5*A0#R(5$(/G

qq7S#>A#+(8"J#-($/(58(<*&(A#(A/%&?(8/(*(.8%?#&8(/AD#<8-(*(.8*GG(/AD#<8-(/+(*(V*<%08"(/AD#<8(O05&#([QCTR1(=&(*??585/&-

"/%(<*&(%$#(*(0//J(8/(J+/<#$$(83#>(O05&#(CTQCER1(=&(83#(0//J-(H*+5*A0#(m(<*&(A#(A/%&?(8/(*&"(/G(83#(83+##(8"J#$(/G

/AD#<8$1(4583/%8(6*H*m$(J/0">/+J35$>-("/%(@/%0?(&/8(A#(*A0#(8/($8/+#(83#$#(?5GG#+#&8(/AD#<8$(5&(/&#(?*8*($8+%<8%+#

O#1'1(*&(*++*"R(/+(J+/<#$$(83#>(</&H#&5#&80"(5&(/&#(0//J1

j/@(0#8(%$(0//,(*8(*&/83#+(#c*>J0#1(.%JJ/$#(*(J#8(<05&5<(&##?$(8/(>*5&8*5&(*(05$8(/G(83#5+(J#8(<05#&8$(O<*8$(*&?(?/'$R1

=8(5$(&#<#$$*+"(G/+(83#>(8/(J%8(A/83(8"J#$(/G(J#8$(5&(83#($*>#(J//0(8/(>*&*'#($<3#?%05&'1(=&$8#*?(/G(>*,5&'(8@/

%&+#0*8#?(<0*$$#$(7*8(*&?(2/'-(@#(<*&(>*,#(7*8(*&?(2/'(A/83($%A<0*$$#$(/G(*()#8(<0*$$1(;35$(@*"-(@#(<*&(%$#(*()#8

*++*"(8/($8/+#(A/83(7*8(*&?(2/'(/AD#<8$1(;3#(G/00/@5&'(*+#(83#(ZSN(*&?(</?#(G/+(835$(#c*>J0#1

Example 2: Pet.java

1| publicpublic classclass GGCRosterLoop

2| {

3| publicpublic staticstatic voidvoid main(String[] args)

4| {

5| GGCMember[] members = newnew GGCMember[3];

//Each indexed variable could be bound to any of the three types: Student, Staff, and Faculty

8| members[0] = newnew Student(90011022L, "John", "Smith", "MATH");

9| members[1] = newnew Staff(90003088L, "Rachel", "Morgan", "Academic Affairs", "SST");

10| members[2] = newnew Faculty(90021028L, "Linda", "Davis", "Academic Affairs", "CHEM");

11|

12| forfor (GGCMember m: members)

13| {

14| System.out.println(m);

15| }

16| }

17|}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 43 of 185http://itec2150.gitlab.io/

Example 2: Cat.java

Example 2: Dog.java

publicpublic classclass Pet

{

privateprivate String name;

privateprivate String ownerName;

privateprivate intint age;

privateprivate String hairColor;

publicpublic Pet(String name, String ownerName, intint age, String hairColor)

{

thisthis.name = name;

thisthis.ownerName = ownerName;

thisthis.age = age;

thisthis.hairColor = hairColor;

}

//getters and setters for name, ownerName, age, and hairColor (not shown)

@Override

publicpublic String toString()

{

returnreturn "Pet[name=" + name + ", ownerName=" + ownerName +

", age=" + age + ", hairColor=" + hairColor + "]";

}

JAVA

publicpublic classclass Cat extendsextends Pet

{

privateprivate booleanboolean longHair;

privateprivate booleanboolean clawed;

publicpublic Cat(String name, String ownerName, intint age, String hairColor,

booleanboolean longHair, booleanboolean clawed)

{

supersuper(name, ownerName, age, hairColor);

thisthis.longHair = longHair;

thisthis.clawed = clawed;

}

//getters and setters for longHair and clawed (not shown)

@Override

publicpublic String toString()

{

returnreturn supersuper.toString() +

" Cat[longHair=" + longHair + ", clawed=" + clawed + "]";

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 44 of 185http://itec2150.gitlab.io/

Example 2: PetCareClients.java

V+/>(83#$#(8@/(#c*>J0#$-(@#(3*H#(0#*+&#?(83*8(@#(<*&(>*,#(/AD#<8$(/G(?5GG#+#&8(8"J#$(+#0*8#?(8/(#*<3(/83#+

83+/%'3(*(</>>/&($%J#+<0*$$1(;3+/%'3(835$(</>>/&($%J#+<0*$$-(@#(<*&(8*,#(*?H*&8*'#(/G(J/0">/+J35$>(*&?

$8/+#(*&?(J+/<#$$(83#$#(/AD#<8$($"$8#>*85<*00"1

F&/83#+(*?H*&8*'#(/G(J/0">/+J35$>(5$(83*8(58(#&*A0#$(*(>#83/?(8/(A#(%$#?(G/+(?5GG#+#&8(8"J#$(/G(?*8*1(;3#(#c*>J0#

J+/'+*>(A#0/@($5>%0*8#$(83*8(83#(J#8(<05&5<($#&?$(*JJ/5&8>#&8(+#>5&?#+$(G/+(83#(&#c8(?*"1

Example 2: PetCareClientsMethod.java

publicpublic classclass Dog extendsextends Pet

{

privateprivate String breed;

publicpublic Dog(String name, String ownerName, intint age, String hairColor,

String breed)

{

supersuper(name, ownerName, age, hairColor);

thisthis.breed = breed;

}

//getter and setter for breed (not shown)

@Override

publicpublic String toString()

{

returnreturn supersuper.toString() + " " + "Dog[breed=" + breed + "]";

}

JAVA

publicpublic classclass PetCareClients

{

publicpublic staticstatic voidvoid main(String[] args)

{

Pet[] pets = newnew Pet[5];

pets[0] = newnew Cat("Fluffy", "Jane", 2, "orange", truetrue, falsefalse);

pets[1] = newnew Dog("Coco", "Linda", 3, "brown", "Poodle");

pets[2] = newnew Dog("Mongo", "William", 1, "white", "Bichon");

pets[3] = newnew Dog("Patch", "Marta", 12, "spotty", "Dalmatian");

pets[4] = newnew Cat("Petey", "Nicholas", 5, "brown", falsefalse, falsefalse);

forfor (Pet p: pets)

{

System.out.println(p);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 45 of 185http://itec2150.gitlab.io/

;3#(>#83/?(appointmentReminder(%$#$(J/0">/+J35$>(8/(*?*J8(8/(?5GG#+#&8(J#8(8"J#$1(;3#(?*8*(8"J#(/G(83#(G5+$8

J*+*>#8#+(5$()#81(43#&(83#(>#83/?(5$(5&H/,#?-(83#(G5+$8(*+'%>#&8(G/+(83#(>#83/?(</%0?(A#(#583#+(7*8(/+(2/'1

4583/%8(J/0">/+J35$>-(@#(@/%0?(&##?(8@/($#J*+*8#(A%8(*0>/$8(83#($*>#(>#83/?$(O>#83/?(/H#+0/*?5&'R-(/&#(G/+

2/'(*&?(/&#(G/+(7*8(O$##(A#0/@R1(=G(*(J#8(3/$J58*0(8*,#$(<*+#(/G(8#&(?5GG#+#&8(8"J#$(/G(J#8$-(@583/%8(J/0">/+J35$>-

8#&($%<3(>#83/?$(@/%0?(A#(&##?#?(*&?(83#(/&0"(?5GG#+#&<#(*>/&'(83#>(5$(83#(?*8*(8"J#(/G(83#(G5+$8(J*+*>#8#+1(=8

@/%0?(A#(H#+"(<%>A#+$/>#1(4583(J/0">/+J35$>-(/&#(>#83/?(5$(*?#d%*8#-(*&?(58(</%0?(r*?*J8r(8/(?5GG#+#&8(J#8

8"J#$(83+/%'3(?"&*>5<(A5&?5&'1

Without Polymorphism of the first parameter, we would need to use method overloading, resulting in repetitive

code.

importimport java.util.Datejava.util.Date;

publicpublic classclass PetCareClientsMethod

{

publicpublic staticstatic voidvoid main(String[] args)

{

Pet[] pets = newnew Pet[5];

pets[0] = newnew Cat("Fluffy", "Jane", 2, "orange", truetrue, falsefalse);

pets[1] = newnew Dog("Coco", "Linda", 3, "brown", "Poodle");

pets[2] = newnew Dog("Mongo", "William", 1, "white", "Bichon");

pets[3] = newnew Dog("Patch", "Marta", 12, "spotty", "Dalmatian");

pets[4] = newnew Cat("Petey", "Nicholas", 5, "brown", falsefalse, falsefalse);

Date date = newnew Date();

//The date (time as well) when this line is executed.

longlong time = date.getTime();

//Total milliseconds from midnight 1/1/1970

time += 24*60*60*1000;

//24 hours from now

forfor (Pet p: pets)

{

appointmentReminder(p, time);

time += 30*60*1000;

// add 30 mins to the time (30*60*1000 milliseconds)

}

publicpublic staticstatic voidvoid appointmentReminder(Pet pet, longlong time)

{

Date date = newnew Date(time);

System.out.println("Dear " + pet.getOwnerName() + ",");

System.out.println(" A kind reminder that " + pet.getName() + "'s appointment is at " + date);

System.out.println("See you soon!");

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 46 of 185http://itec2150.gitlab.io/

3.5. Abstract Class

4#(@500(5&8+/?%<#(*A$8+*<8(<0*$$(@583(*(</&<+#8#(#c*>J0#1(4#(@500(@+58#(*(</>J%8#+('*>#(*&?(83#('*>#(5&<0%?#$

?5GG#+#&8($3*J#$-($%<3(*$(<5+<0#$-(+#<8*&'0#$-(#8<1(=&(/+?#+(8/(J+#H#&8(83#('*>#($J*<#(G+/>('#885&'(8//(<+/@?#?-(83#

J+/'+*>(&##?$(8/(,&/@(83#(8/8*0(*+#*(/<<%J5#?(A"(83#($3*J#$1(F$(D%$8($8*8#?(G+/>(83#(J+#H5/%$($#<85/&-(5&(/+?#+(8/

>*&*'#(*00(83#$#(?5GG#+#&8($3*J#$(5&(*($"$8#>*85<(>*&&#+-(58(5$('//?(8/(</&&#<8(*00(83#$#($3*J#$(@583(*(</>>/&

$%J#+<0*$$1(;3#(G/00/@5&'(5$(83#(ZSN(G/+(835$(*JJ05<*85/&1

;3#(G/00/@5&'(5$(83#($%J#+<0*$$(.3*J#1(;3#(<0*$$(>5'38(</&8*5&(/83#+(*88+5A%8#$-($%<3(*$(c(*&?("(<//+?5&*8#$(*&?

$J##?$(*0/&'(c(*&?("(?5+#<85/&$-(A%8(@#(@500($,5J(83#>(8/(>*,#(83#(#c*>J0#(D%$8(*?#d%*8#(8/(5&8+/?%<#(83#(&#@

</&<#J81

Example 3: Shape.java

publicpublic staticstatic voidvoid appointmentReminder(Dog pet, longlong time)

{

Date date = newnew Date(time);

System.out.println("Dear " + pet.getOwnerName() + ",");

System.out.println(" A kind reminder that " + pet.getName() + "'s appointment is at " + date);

System.out.println("See you soon!");

}

publicpublic staticstatic voidvoid appointmentReminder(Cat pet, longlong time)

{

Date date = newnew Date(time);

System.out.println("Dear " + pet.getOwnerName() + ",");

System.out.println(" A kind reminder that " + pet.getName() + "'s appointment is at " + date);

System.out.println("See you soon!");

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 47 of 185http://itec2150.gitlab.io/

9/%(@500(&/85<#(*(</%J0#(/G(&#@(835&'$(5&(83#(*A/H#(<0*$$(?#G5&585/&1(U&(83#(<0*$$(3#*?#+-(83#+#(5$(*(&#@(,#"(@/+?

abstract1(;35$(,#"(@/+?(*0$/($3/@$(%J(5&(83#(>#83/?(area-(@35<3(3*$(&/(>#83/?(A/?"1(l#>#>A#+(83*8(.3*J#(5$

83#($%J#+(<0*$$(G/+(?5GG#+#&8(</&<+#8#($3*J#$1(.5&<#(83#(<0*$$(Shape(?/#$(&/8(+#J+#$#&8(*(</&<+#8#($3*J#-(83#+#(5$

+#*00"(&/(@*"(8/(<*0<%0*8#(83#(*+#*1(4#(%$#(83#(,#"(@/+?(abstract(8/(+#J+#$#&8(83*8(83#(>#83/?(5$(&/8

5>J0#>#&8#?(/&(J%+J/$#1(F$(0/&'(*$(83#+#(5$(/&#(*A$8+*<8(>#83/?-(83#(<0*$$(3#*?#+(>%$8(5&<0%?#(83#(,#"@/+?

abstract(8/(>*+,(83#(<0*$$(*$(*A$8+*<81(=G(*(<0*$$(5$(*A$8+*<8-("/%(<*&&/8(5&$8*&85*8#(83#(<0*$$-(83*8(5$-("/%(<*&&/8

<+#*8#(*&(/AD#<8(O*&(5&$8*&<#R(/G(835$(<0*$$1

9/%(>5'38(A#(@/&?#+5&'(83*8(5G(83#(>#83/?(area(<*&&/8(A#(5>J0#>#&8#?(5&(83#(Shape(<0*$$-(@3"(?/(@#(5&<0%?#

83#(>#83/?(*8(*00\(4583/%8(58-(83#(Shape(<0*$$(</%0?(A#(D%$8(&/+>*0(&/&Q*A$8+*<8(<0*$$1(;/(%&?#+$8*&?(83#(J%+J/$#

/G(*&(*A$8+*<8(<0*$$-(0#8(%$(0//,(*8(83#(G/00/@5&'(?#G5&585/&(G/+(83#($%A<0*$$(75+<0#1(j/8#(83*8(@#(?/(&/8(@*&8(75+<0#(8/

A#(*&(*A$8+*<8(<0*$$-($5&<#(@#(@500(&##?(8/(<+#*8#(75+<0#(/AD#<8$(5&(83#('*>#1(;3*8(5$(@3"(@#(?/(&/8(5&<0%?#(83#

,#"@/+?(abstract(/&(83#(<0*$$(3#*?#+1

Example 3: Circle.java (Incomplete)

publicpublic abstractabstract classclass Shape

{

privateprivate String color;

privateprivate booleanboolean filled;

publicpublic Shape(String color, booleanboolean filled)

{

supersuper();

thisthis.color = color;

thisthis.filled = filled;

}

//getters and setters for color and filled (not shown)

@Override

publicpublic String toString()

{

returnreturn "[color=" + color + ", filled=" + filled + "]";

}

publicpublic abstractabstract doubledouble area();

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 48 of 185http://itec2150.gitlab.io/

9/%(@500(&/85<#(83*8(83#+#(5$(&/(>#83/?(?#G5&585/&(G/+(area(5&(83#(75+<0#(<0*$$1(=&(*&(=2b($%<3(*$(b<05J$#(/+(=&8#0056-

"/%(@500($##(*(</>J50#(#++/+(*8(83#(<0*$$(3#*?#+1(.##(83#(G/00/@5&'(5>*'#B

F$($3/@&(*A/H#-(83#(</>J50#+(+#J/+8$(*&(#++/+(5G(*&(*A$8+*<8(>#83/?(5$(&/8(/H#++5??#&(@583(*&(*<8%*0

5>J0#>#&8*85/&(A"(*(&/&Q*A$8+*<8(<0*$$1(;35$(5$(83#(+#*$/&(G/+(5&<0%?5&'(83#(*A$8+*<8(>#83/?(area(5&(83#($%J#+

<0*$$(.3*J#1(=8(rG/+<#$r(*00(&/&Q*A$8+*<8($%A<0*$$#$(8/(J+/H5?#(*&(*<8%*0(?#G5&585/&(G/+(83#(>#83/?1

=G("/%(<05<,(/&(83#(G5+$8(d%5<,(G5c-("/%(@500('#8(*(>#83/?($8%A(G/+(/H#++5?5&'(83#(>#83/?(*+#*(*$($3/@&(A"(83#(0*$8

>#83/?(5&(83#(G/00/@5&'(</?#B

Example 3: Circle.java (Almost Complete)

publicpublic classclass Circle extendsextends Shape

{

privateprivate intint x, y;

privateprivate intint radius;

publicpublic Circle(String color, booleanboolean filled, intint x, intint y, intint radius)

{

supersuper(color, filled);

thisthis.x = x; thisthis.y = y; thisthis.radius = radius;

}

//getters and setters for x, y, and radius (not shown)

@Override

publicpublic String toString()

{

returnreturn "Circle [@(" + x + ", " + y + "), r: " + radius + "] " + supersuper.toString();

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 49 of 185http://itec2150.gitlab.io/

4#(@500(+#J0*<#(83#(*%8/Q'#&#+*8#?($8%A(G/+(>#83/?(*+#*(@583(83#(G/00/@5&'(*<8%*0(5>J0#>#&8*85/&1

Example 3: The area method in Circle.java

;3#(G/00/@5&'(5$(83#(<0*$$(?#G5&585/&(G/+(*&/83#+($%A<0*$$(l#<8*&'0#1(4#(@500($,5J(/83#+($3*J#$(O#1'1(8+5*&'0#R(8/

J+#H#&8(83#(#c*>J0#(8*,5&'(%J(8//(>%<3($J*<#(A%8($8500(*?#d%*8#(G/+(5&8+/?%<5&'(83#(</&<#J81

Example 3: Rectangle.java

publicpublic classclass Circle extendsextends Shape

{

privateprivate intint x, y;

privateprivate intint radius;

publicpublic Circle(String color, booleanboolean filled, intint x, intint y, intint radius)

{

supersuper(color, filled);

thisthis.x = x; thisthis.y = y; thisthis.radius = radius;

}

//getters and setters for x, y, and radius (not shown)

@Override

publicpublic String toString()

{

returnreturn "Circle [@(" + x + ", " + y + "), r: " + radius + "] " + supersuper.toString();

}

@Override

publicpublic doubledouble area()

{

// TODO Auto-generated method stub

returnreturn 0;

}

JAVA

@Override

publicpublic doubledouble area()

{

returnreturn Math.PI * radius * radius;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 50 of 185http://itec2150.gitlab.io/

3.5.1. Polymorphism through Abstract Class

bc<#J8(83*8("/%(<*&&/8(5&$8*&85*8#(*&(*A$8+*<8(<0*$$(O<*&&/8(<+#*8#(*&(/AD#<8(/G(83#(<0*$$R-("/%(%$#(*&(*A$8+*<8(<0*$$

83#($*>#(@*"(*$(*(+#'%0*+($%J#+(<0*$$1(;3#(G/00/@5&'(</?#($3/@$(83*8(@#(<*&($8/+#(/AD#<8$(/G(?5GG#+#&8(8"J#$(O75+<0#

*&?(l#<8*&'0#-(A/83(.3*J#m$($%A<0*$$#$R(5&(*(Shape(*++*"(*&?(J+/<#$$(83#>(5&(*($"$8#>*85<(>*&&#+(A#<*%$#(/G

J/0">/+J35$>1

Example 3: AreasOfAllShapes.java

publicpublic classclass Rectangle extendsextends Shape

{

privateprivate intint x, y;

privateprivate intint width, height;

publicpublic Rectangle(String color, booleanboolean filled, intint x, intint y, intint width, intint height)

{

supersuper(color, filled);

thisthis.x = x;

thisthis.y = y;

thisthis.width = width;

thisthis.height = height;

}

//getters and setters for x, y, width, and height (not shown)

@Override

publicpublic doubledouble area()

{

returnreturn width*height;

}

@Override

publicpublic String toString()

{

returnreturn "Rectangle [@ (" + x + ", " + y + "), w: " + width + ", h: " + height + "] " +

supersuper.toString();

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 51 of 185http://itec2150.gitlab.io/

U%8J%8(/G(83#(J+/'+*>B

3.5.2. An Experiment: Removing the Abstract Methods from the Super Class

;3#(J+#H5/%$(#c*>J0#($3/@$(83*8(*A$8+*<8(>#83/?$-(#H#&(83/%'3(&/8(5>J0#>#&8#?(5&(83#($%J#+(<0*$$-(@500(G/+<#(*00

83#(&/&Q*A$8+*<8($%A<0*$$#$(8/(5>J0#>#&8(83#>1(!#+#(@#(@500(?/(*&(#cJ#+5>#&8(8/(3#0J("/%(%&?#+$8*&?(83#

*A$8+*<8(>#83/?(G+/>(*&/83#+(*&'0#1

9/%(>5'38(A#(@/&?#+5&'(@3*8(</%0?(3*JJ#&(5G(@#(D%$8(>*,#(83#($%J#+(<0*$$(Shape(&/&Q*A$8+*<8(A"(+#>/H5&'(83#

*A$8+*<8(>#83/?(area(*08/'#83#+1(4#(<*&($5>J0"(5>J0#>#&8(83#(*+#*(>#83/?(5&(83#($%A<0*$$#$(75+<0#(*&?

l#<8*&'0#1(=G(@#(+#>/H#(83#(*A$8+*<8(>#83/?(area(G+/>(Shape(*&?(>*,#(58(*(+#'%0*+(<0*$$(@350#(,##J5&'(83#

>#83/?(area(5&(75+<0#(*&?(83*8(5&(l#<8*&'0#(5&8*<8-(@#(@500('#8(83#(G/00/@5&'(</>J50#(#++/+1

1| publicpublic classclass AreasOfAllShapes

2| {

3| publicpublic staticstatic voidvoid main(String[] args)

4| {

5| Shape[] shapes = newnew Shape[3];

7| shapes[0] = newnew Circle("blue", truetrue, 30, 30, 5);

// center at (30, 30), radius 5

8| shapes[1] = newnew Rectangle("orange", falsefalse, 50, 100, 30, 15);

// upper-left corner (50, 100), width

30, height 15

9| shapes[2] = newnew Circle("red", falsefalse, 250, 250, 20);

// center at (250, 250), radius 20

10|

11| intint area = 0;

12| forfor (Shape s: shapes)

13| {

14| area += s.area();

15| }

16| System.out.println("Total area of the shapes: " + area);

17| }

18| }

JAVA

Total area of the shapes: 1784

4/5/21, 10)50 PMIntermediate Programming

Page 52 of 185http://itec2150.gitlab.io/

4#(@500('#8(*(</>J50#(#++/+(/&(05&#(CK(@583(83#(>#83/?(5&H/<*85/&(s.area()1(;3#+#(>%$8(A#(*(area(>#83/?(5&(83#

Shape(<0*$$(5&(/+?#+(8/('#8(83#(</?#(</>J50#?1(V+/>(835$(#cJ#+5>#&8-(@#(<*&($##(83*8(83#(*A$8+*<8(>#83/?(3*$(58$

$"&8*<85<(J%+J/$#(*&?(>%$8(A#(5&<0%?#?(5&(83#($%J#+(<0*$$(5&(/+?#+(G/+(J/0">/+J35$>(8/(@/+,1

4#(<*&(*0$/(</&G5+>(83*8(H*+5*A0#(m(5$(A/%&?(8/(?5GG#+#&8(/AD#<8$(?%+5&'(+%&(85>#(O83%$(<*00#?(?"&*>5<(A5&?5&'R

A%8(&/8(*8(</>J50#(85>#1(=&(G*<8-(G/+(>/$8(<*$#$-(58(5$(5>J/$$5A0#(8/(,&/@(@3*8(*(H*+5*A0#(5$(A/%&?(8/(*8(</>J50#

85>#1

3.6. Interface

;3#($"&8*c(G/+(?#G5&5&'(*&(5&8#+G*<#(5$(H#+"($5>50*+(8/(83*8(G/+(?#G5&5&'(*(<0*$$1(=&8#+G*<#(</&8*5&$(/&0"(J%A05<

*A$8+*<8(>#83/?O$R1(=8(?/#$(&/8(</&8*5&(*&"(*88+5A%8#$(*&?(83#+#G/+#(?/#$(&/8(</&8*5&(*&"(</&$8+%<8/+$(O&/835&'(8/

5&585*05a#R1(;3#(G/00/@5&'(5$(83#(5&8#+G*<#(?#G5&585/&(G/+(7/>J*+*A0#(O5&<0%?#?(5&(83#($8*&?*+?(6*H*(05A+*+"

388J$BPP?/<$1/+*<0#1</>P#&PD*H*PD*H*$#PCKP?/<$P*J5PD*H*1A*$#PD*H*P0*&'P7/>J*+*A0#138>0R1(4#(<*&($##(83*8(5&$8#*?(/G

class-(83#(,#"@/+?(/&(83#(3#*?#+(5$(interface1(V/+(>#83/?O$R-(83#(,#"@/+?$(public(*&?(abstract(*+#($,5JJ#?-

$5&<#(*00(>#83/?$(*+#(J%A05<(*&?(*A$8+*<81

Interface Comparable (Contained in the Java Library)

Comparing Abstract Classes and InterfacesB(9/%(>*"($*"(83*8(=&8#+G*<#(5$(+#*00"(*($J#<5*0(*A$8+*<8(<0*$$(83*8(/&0"

</&8*5&$(*A$8+*<8(>#83/?$1(=&(G*<8-(835$(5$(&/8(</++#<81(;3#(5&8#+G*<#(>#<3*&5$>(5$(+#*00"(r5&(J*+*00#0r(@583(83#(<0*$$

5&3#+58*&<#(>#<3*&5$>1(=8(5$(>#*&8(G/+(*(<0*$$(8/(r5>J0#>#&8r(83#(>#83/?$1(F(<0*$$(<*&(#c8#&?(*($%J#+(<0*$$(/+

5>J0#>#&8(*&(5&8#+G*<#1(=8(<*&(*0$/(#c8#&?(*($%J#+(<0*$$(*&?(5>J0#>#&8$(*&(5&8#+G*<#(*8(83#($*>#(85>#1(F&(*A$8+*<8

<0*$$(5$($8500(*(<0*$$1(;3*8(5$-(58(5$(@583(83#(<0*$$(5&3#+58*&<#(>#<3*&5$>(83*8(5$(r5&(J*+*00#0r(@583(83#(5&8#+G*<#

5>J0#>#&8*85/&(>#<3*&5$>1

V/+(#c*>J0#-(83#(G/00/@5&'(<0*$$(5>J0#>#&8$(7/>J*+*A0#1(;/(5>J0#>#&8(*&(5&8#+G*<#-(OCR(83#(<0*$$($3/%0?(A#

>*+,#?(/&(83#(3#*?#+(*$(r5>J0#>#&8$(83#(5&8#+G*<#r(*&?(OER(83#(*A$8+*<8(>#83/?$(5&(83#(5&8#+G*<#(@500(&##?(8/(A#

/H#++5??#&-(/83#+@5$#(83#"(*+#(r5&3#+58#?r(*$(5$(*$(*A$8+*<8(>#83/?$1

Example 4: Circle.java

publicpublic interfaceinterface Comparable<T>

{

intint compareTo(T o);

/*Compares this object with the specified object for order. Returns a negative integer, zero, or a positive

integer as this object is less than, equal to, or greater than the specified object.*/

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 53 of 185http://itec2150.gitlab.io/

9/%(<*&($##(83*8(835$(5$(83#($*>#(75+<0#(<0*$$(*$(83#(0*$8($#<85/&-(A%8(@583(8@/(835&'$(*??#?B

F8(83#(#&?(/G(83#(<0*$$(3#*?#+-(implements Comparable<Shape>(5$(*??#?1

F(compareTo(>#83/?(5$(*??#?(8/(83#(<0*$$(?#G5&585/&1(;35$(5$($5>50*+(8/(/H#++5?#(*(>#83/?(5&(*($%J#+(<0*$$1(;3#

</>J*+#;/(>#83/?(+#8%+&$(*(J/$585H#(5&8#'#+(C(5G(83#(75+<0#(/AD#<8m$(*+#*(5$('+#*8(83*&(83#(J*+*>#8#+(oo$(*+#*-

+#8%+&$(*(&#'*85H#(5&8#'#+(QC(5G(0#$$(83*&-(*&?(+#8%+&$(T(5G(#d%*01

4#(</%0?(?/(83#($*>#(G/+(83#(l#<8*&'0#(<0*$$(A"(>*,5&'(58(5>J0#>#&8(83#(7/>J*+*A0#(5&8#+G*<#B

Example 4: Rectangle.java

publicpublic classclass Circle extendsextends Shape implementsimplements Comparable<Shape>

{

privateprivate intint x, y;

privateprivate intint radius;

publicpublic Circle(String color, booleanboolean filled, intint x, intint y, intint radius)

{

supersuper(color, filled);

thisthis.x = x; thisthis.y = y; thisthis.radius = radius;

}

//getters and setters for x, y and radius (not shown)

@Override

publicpublic String toString()

{

returnreturn "Circle [@(" + x + ", " + y + "), r: " + radius + "] " + supersuper.toString();

}

@Override

publicpublic doubledouble area()

{

returnreturn Math.PI * radius * radius;

}

@Override

publicpublic intint compareTo(Shape o)

{

ifif (thisthis.area() > o.area())

returnreturn 1;

elseelse ifif (thisthis.area() < o.area())

returnreturn -1;

elseelse

returnreturn 0;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 54 of 185http://itec2150.gitlab.io/

Example 4: Shape.java

`/83(83#(75+<0#(*&?(l#<8*&'0#(<0*$$#$(3*H#(&/(</>J50*85/&(#++/+$1(9/%(<*&($##(83*8(*(<0*$$(<*&(#c8#&?(*($%J#+(<0*$$

*&?(5>J0#>#&8(*&(5&8#+G*<#(*8(83#($*>#(85>#1(F(<0*$$(<*&(/&0"(#c8#&?(/&#($%J#+Q<0*$$-(3/@#H#+-(*(<0*$$(<*&

5>J0#>#&8(>/+#(83*&(/&#(5&8#+G*<#-(@35<3(@#(@500(8*0,(*A/%8(0*8#+1

j/@(0#8m$(0//,(*8(83#(G/00/@5&'(J+/'+*>-(@35<3(5&8#&?$(8/(%$#(83#(compareTo(>#83/?$(5&(75+<0#(*&?(l#<8*&'0#(8/

?#8#+>5&#(83#($3*J#(@583(83#(>*c5>%>(*+#*1(Z&G/+8%&*8#0"-(58(</&8*5&$(*(</>J50#(#++/+1

publicpublic classclass Rectangle extendsextends Shape implementsimplements Comparable<Shape>

{

privateprivate intint x, y;

privateprivate intint width, height;

publicpublic Rectangle(String color, booleanboolean filled, intint x, intint y, intint width, intint height)

{

supersuper(color, filled);

thisthis.x = x;

thisthis.y = y;

thisthis.width = width;

thisthis.height = height;

}

//getters and setters for x, y, width and height (not shown)

@Override

publicpublic String toString()

{

returnreturn "Rectangle [@ (" + x + ", " + y + "), w: " + width + ", h: " + height + "] " +

supersuper.toString();

}

@Override

publicpublic doubledouble area()

{

returnreturn width*height;

}

@Override

publicpublic intint compareTo(Shape o)

{

ifif (thisthis.area() > o.area())

returnreturn 1;

elseelse ifif (thisthis.area() < o.area())

returnreturn -1;

elseelse

returnreturn 0;

}

JAVA

The same as Shape.java in Example 3

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 55 of 185http://itec2150.gitlab.io/

;3#+#(5$(*&(#++/+(G/+(p.compareTo(maxShape)-($5&<#(83#(H*+5*A0#(po$(8"J#(5$(.3*J#(*&?(83#+#(5$(&/(compareTo

>#83/?(?#G5&#?(5&(83#(.3*J#(<0*$$1(;35$(5$(*($5>50*+(#++/+(*$(83#(/&#(@#($##(5&(83#(#cJ#+5>#&8(G/+(*A$8+*<8(<0*$$1

;3#($%J#+(<0*$$(Shape(&##?$(8/(</&8*5&(83#(>#83/?(5&(/+?#+(G/+(83#(*A/H#(</?#(8/(A#(</>J50#?1

;/(G5c(835$(J+/A0#>-(@#(@500(5>J0#>#&8(83#(compareTo(>#83/?(5&(83#(.3*J#(<0*$$-(5&$8#*?(/G(5&(83#(75+<0#(<0*$$

*&?(83#(l#<8*&'0#(<0*$$1(;35$(@*"-(@#(/&0"(&##?(8/(5>J0#>#&8(83#(>#83/?(/&<#(*&?(58(@500(A#(5&3#+58#?(A"(*00(83#

$%A<0*$$#$(O75+<0#(*&?(l#<8*&'0#R1(4#(@500(,##J(83#(75+<0#(*&?(l#<8*&'0#(<0*$$#$(83#($*>#(*$(83#(J+#H5/%$($#<85/&

O@583/%8(83#(compareTo(>#83/?R1(.##(A#0/@(G/+(83#(&#@(.3*J#(<0*$$1

;3#(G/00/@5&'(5$(83#(ZSN(83*8(<*J8%+#$(83#(+#0*85/&$35J(*>/&'(83#(<0*$$#$(*&?(83#(5&8#+G*<#(5&(bc*>J0#(L1(;3#

?/88#?(05&#(*++/@(+#J+#$#&8$(83#(5>J0#>#&8*85/&(+#0*85/&$35J1

4/5/21, 10)50 PMIntermediate Programming

Page 56 of 185http://itec2150.gitlab.io/

Example 5: Shape.java

4/5/21, 10)50 PMIntermediate Programming

Page 57 of 185http://itec2150.gitlab.io/

Example 5: Circle.java

Example 5: Rectangle.java

Example 5: MaxShape.java

43#&("/%(+%&(S*c.3*J#-(83#(J+/'+*>(@500(?5$J0*"(83#(G/00/@5&'B

publicpublic abstractabstract classclass Shape implementsimplements Comparable<Shape>

{

privateprivate String color;

privateprivate booleanboolean filled;

publicpublic Shape(String color, booleanboolean filled)

{

supersuper();

thisthis.color = color;

thisthis.filled = filled;

}

//getters and setters for color and filled (not shown)

publicpublic abstractabstract doubledouble area();

@Override

publicpublic String toString()

{

returnreturn "[color=" + color + ", filled=" + filled + "]";

}

@Override

publicpublic intint compareTo(Shape o)

{

ifif (thisthis.area() > o.area())

returnreturn 1;

elseelse ifif (thisthis.area() < o.area())

returnreturn -1;

elseelse

returnreturn 0;

}

JAVA

The same as Circle.java in Example 3

JAVA

The same as Circle.java in Example 3

JAVA

The same as MaxShape.java in Example 4

JAVA

The shape with maximum area is: Circle [@(250, 250), r: 20.0] [color=red, filled=false]

4/5/21, 10)50 PMIntermediate Programming

Page 58 of 185http://itec2150.gitlab.io/

N#8(%$(0//,(*8(83#(Shape(<0*$$(>/+#(<*+#G%00"1(9/%(@500($##(83*8(83#(>#83/?(area(5$(*A$8+*<81(9/%(>5'38(@/&?#+

@3#83#+(58(5$(U_(G/+(83#(compareTo(>#83/?(8/(5&H/,#(83#(area(>#83/?1(=8(5$(U_(A#<*%$#(*&(*A$8+*<8(<0*$$(<*&&/8

A#(5&$8*&85*8#?1(;3#(*A$8+*<8(>#83/?(area(@500(A#(/H#++5??#&(A"(83#($%A<0*$$#$(75+<0#(*&?(l#<8*&'0#(*&?(83#

compareTo(>#83/?(@500(A#(5&3#+58#?(A"(83#($%A<0*$$#$(75+<0#(*&?(l#<8*&'0#1(=&(83#(0//J(O05&#(CCQCMR(5&(83#(>*5&

>#83/?-(H*+5*A0#$(p(*&?(maxShape(*+#(A/%&?(8/(#583#+(*(75+<0#(/+(l#<8*&'0#(/AD#<8(*8(*&"(J/5&8(?%+5&'(#c#<%85/&1

;3#(5&3#+58#?(>#83/?(compareTo(@500(5&H/,#(83#(J+/J#+(area(>#83/?(?#G5&#?(5&(#583#+(75+<0#(/+(l#<8*&'0#1

;35$(+#*00"($3/@$(*&/83#+(*?H*&8*'#(/G(%$5&'(*A$8+*<8(<0*$$#$1(=8(3/0?$(</&<+#8#(>#83/?$(83*8(<*&(A#(5>J0#>#&8#?

$/(83*8(83#($%AQ<0*$$#$(?/(&/8(3*H#(8/(5>J0#>#&8(83#>(*&?(<*&(5&3#+58(83#>(*$(83#"(*+#1(=8(<*&(*0$/(3/0?(*A$8+*<8

>#83/?$(83*8(58(<*&&/8(5>J0#>#&8(A%8(@500(rG/+<#r(*00(83#(&/&Q*A$8+*<8($%A<0*$$#$(8/(5>J0#>#&8(83#5+(/@&(H#+$5/&1

3.6.1. A Class Can Implement Multiple Interfaces

bH#&(83/%'3(*(<0*$$(<*&(/&0"(#c8#&?(/&#(*&?(/&0"(/&#($%J#+(<0*$$-(*(<0*$$(<*&(5>J0#>#&8(>%085J0#(5&8#+G*<#$1(4#

@500(>*,#(83#(.3*J#(<0*$$(5>J0#>#&8(8@/(5&8#+G*<#$(Comparable(*&?(Animation1

;3#(G/00/@5&'(5$(83#(Animation(5&8#+G*<#(83*8(</&8*5&$(8@/(J%A05<(*A$8+*<8(>#83/?$(talk(*&?(flipRight1

Example 6: Animation.java

43#&(*(<0*$$(5>J0#>#&8$(>/+#(83*&(/&#(5&8#+G*<#-(83#(5&8#+G*<#(&*>#$(*+#($#J*+*8#?(@583(</>>*O$R(/&(83#(<0*$$

3#*?#+1

Example 6: Shape.java

publicpublic interfaceinterface Animation

{

voidvoid talk();

//Simulate talking by displaying (printing) a message

voidvoid flipRight();

//flip to the right (mirror)

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 59 of 185http://itec2150.gitlab.io/

;3#(.3*J#(<0*$$(/&0"(5>J0#>#&8$(83#(talk(>#83/?(/G(83#(8@/(>#83/?$(5&(83#(Animation(5&8#+G*<#1(;3#(flipRight

>#83/?(5$(&/8(5>J0#>#&8#?(5&(.3*J#-($/(58(5$(r5&3#+58#?r(G+/>(83#(5&8#+G*<#(*$(5$-(83*8(5$-(58(5$($8500(*&(*A$8+*<8

>#83/?(5&(83#(.3*J#(<0*$$1(=8(5$(+#*00"(&/8(J/$$5A0#(8/(5>J0#>#&8(83#(flipRight(>#83/?(3#+#-($5&<#(3/@(*($3*J#(G05J$

?#J#&?$(/&(@3*8(83#(*<8%*0($3*J#(58(5$1(;35$(>#83/?(@500(&##?(8/(A#(5>J0#>#&8#?(5&(83#(</&<+#8#($3*J#(<0*$$#$-

75+<0#(*&?(l#<8*&'0#(O$##(A#0/@R1

;3#(G/00/@5&'(5$(83#(ZSN(83*8(<*J8%+#$(83#(+#0*85/&$35J(*>/&'(83#(<0*$$#$(*&?(83#(5&8#+G*<#(5&(bc*>J0#(M1

publicpublic abstractabstract classclass Shape implementsimplements Comparable<Shape>, Animation

{

privateprivate String color;

privateprivate booleanboolean filled;

publicpublic Shape(String color, booleanboolean filled)

{

supersuper();

thisthis.color = color;

thisthis.filled = filled;

}

//getters and setters for color and filled (not shown)

publicpublic abstractabstract doubledouble area();

@Override

publicpublic String toString()

{

returnreturn "[color=" + color + ", filled=" + filled + "]";

}

@Override

publicpublic intint compareTo(Shape o)

{

ifif (thisthis.area() > o.area())

returnreturn 1;

elseelse ifif (thisthis.area() < o.area())

returnreturn -1;

elseelse

returnreturn 0;

}

@Override

publicpublic voidvoid talk()

{

System.out.println("I am " + thisthis.toString());

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 60 of 185http://itec2150.gitlab.io/

Example 6: Circle.java

43#&(*(<5+<0#(G05J$(8/(83#(+5'38-(58(G05J$(/&(83#(H#+85<*0(8*&'#&8(/&(83#(+5'38-($/(58$(&#@(c(<//+?5&*8#(5$(83#(<%++#&8(c

<//+?5&*8#(J0%$(E(s(+*?5%$1

Example 6: Rectangle.java

publicpublic classclass Circle extendsextends Shape

{

privateprivate intint x, y;

privateprivate intint radius;

publicpublic Circle(String color, booleanboolean filled, intint x, intint y, intint radius)

{

supersuper(color, filled);

thisthis.x = x; thisthis.y = y; thisthis.radius = radius;

}

//getters and setters for x, y, and radius (not shown)

@Override

publicpublic String toString()

{

returnreturn "Circle [@(" + x + ", " + y + "), r: " + radius + "] " + supersuper.toString();

}

@Override

publicpublic doubledouble area()

{

returnreturn Math.PI * radius * radius;

}

@Override

publicpublic voidvoid flipRight()

{

x = x + 2 * radius;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 61 of 185http://itec2150.gitlab.io/

43#&(*(+#<8*&'0#(G05J$(8/(83#(+5'38-(58(G05J$(/&(83#(+5'38(H#+85<*0(#?'#-(83#(/+5'5&*0(%JJ#+(+5'38(</+&#+(A#</>#$(83#

%JJ#+(0#G8(</+&#+(G/+(83#(+#<8*&'0#(*8(83#(&#@(0/<*85/&1(;3#+#G/+#-(83#(&#@(c(<//+?5&*8#(/G(83#(+#<8*&'0#(5$(83#

/+5'5&*0(H*0%#(J0%$(83#(@5?831

;3#(</?#(A#0/@(@500(%8505a#(J/0">/+J35$>(8/(0#8(#*<3($3*J#(/AD#<8(O@35<3(</%0?(A#(75+<0#(/+(l#<8*&'0#R(8*0,-(G05J

+5'38-(*&?(83#&(8*0,(*'*5&1

Example 6: AnimateShapes.java

publicpublic classclass Rectangle extendsextends Shape

{

privateprivate intint x, y;

privateprivate intint width, height;

publicpublic Rectangle(String color, booleanboolean filled, intint x, intint y, intint width, intint height)

{

supersuper(color, filled);

thisthis.x = x;

thisthis.y = y;

thisthis.width = width;

thisthis.height = height;

}

//getters and setters for x, y, width, height

@Override

publicpublic String toString()

{

returnreturn "Rectangle [@ (" + x + ", " + y + "), w: " + width + ", h: " + height + "] " +

supersuper.toString();

}

@Override

publicpublic doubledouble area()

{

returnreturn width*height;

}

@Override

publicpublic voidvoid flipRight()

{

x = x + width;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 62 of 185http://itec2150.gitlab.io/

;3#(G/00/@5&'(5$(83#(/%8J%8(/G(83#(J+/'+*>1(FG8#+(G05JJ5&'(+5'38-(*(<5+<0#(@583(<#&8#+(*8(OIT-(ITR(*&?(+*?5%$(L

A#</>#$(*(<5+<0#(*8(OKT-(ITR(*&?(+*?5%$(&/8(<3*&'#?e(*(+#<8*&'0#(@583(83#(%JJ#+Q0#G8(</+&#+(*8(OLT-(CTTR(@583(@5?83

IT(A#</>#$(*(+#<8*&'0#(*8(O[T-(CTTR(*&?(?5>#&$5/&(&/8(<3*&'#?e(*&?($/(/&1

3.6.2. Polymorphism through Interface

;3#(J/0">/+J35$>(#c*>J0#$($/(G*+(*+#(*00(83+/%'3($%J#+(<0*$$#$1(=&(835$($#<85/&-(@#(@500($##(83#(*>*a5&'(J/@#+(/G

J/0">/+J35$>(83+/%'3(5&8#+G*<#-(@35<3(#&*A0#$($"$8#>*85<*00"($8/+5&'(*&?(J+/<#$$5&'($##>5&'0"(%&+#0*8#?

/AD#<8$1

V5+$8-(0#8(%$(0//,(*8(*(&#@(<0*$$-(Text-(83*8(5$(H#+"(?5GG#+#&8(G+/>(Shape1(=8$(/&0"(+#0*85/&$35J(8/(Shape(5$(83*8(58(*0$/

5>J0#>#&8$(83#(Animation(5&8#+G*<#1

Example 6: Text.java

publicpublic classclass AnimateShapes

{

publicpublic staticstatic voidvoid main(String[] args)

{

Shape[] shapes = newnew Shape[3];

shapes[0] = newnew Circle("blue", truetrue, 30, 30, 5);

// center at (30, 30), radius 5

shapes[1] = newnew Rectangle("orange", falsefalse, 50, 100, 30, 15);

// upper-left corner (50, 100), width 30,

height 15

shapes[2] = newnew Circle("red", falsefalse, 250, 250, 20);

// center at (250, 250), radius 20

forfor (Shape p: shapes)

{

p.talk();

p.flipRight();

p.talk();

System.out.println();

}

JAVA

I am Circle [@(30, 30), r: 5] [color=blue, filled=true]

I am Circle [@(40, 30), r: 5] [color=blue, filled=true]

I am Rectangle [@ (50, 100), w: 30, h: 15] [color=orange, filled=false]

I am Rectangle [@ (80, 100), w: 30, h: 15] [color=orange, filled=false]

I am Circle [@(250, 250), r: 20] [color=red, filled=false]

I am Circle [@(290, 250), r: 20] [color=red, filled=false]

4/5/21, 10)50 PMIntermediate Programming

Page 63 of 185http://itec2150.gitlab.io/

`/83(>#83/?$(5&(83#(Animation(5&8#+G*<#(*+#(5>J0#>#&8#?1(V/+(83#(;#c8(<0*$$-(G05JJ5&'(8/(83#(+5'38(>#*&$(+#H#+$*0

/G(83#($8+5&'(8#c81

Example 6: AnimateShapesTexts.java

publicpublic classclass Text implementsimplements Animation

{

privateprivate String text;

publicpublic Text(String text)

{

thisthis.text = text;

}

//getter and setter for text (not shown)

@Override

publicpublic String toString()

{

returnreturn "Text [text=" + text + "]";

}

@Override

publicpublic voidvoid talk()

{

System.out.println("I am " + thisthis.toString());

}

@Override

publicpublic voidvoid flipRight()

{

//reverse the text

String newText = "";

forfor (intint i = text.length()-1; i >= 0; i--)

{

newText = newText + text.charAt(i);

}

text = newText;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 64 of 185http://itec2150.gitlab.io/

;3#(</?#(*A/H#(?#>/&$8+*8#$(83*8(*&(5&8#+G*<#(<*&(A#(%$#?(*$(*(?*8*(8"J#1(=&(*($#&$#-(*(<0*$$(5>J0#>#&85&'(*&

5&8#+G*<#(5$($5>50*+(8/(*($%A<0*$$(#c8#&?5&'(*($%J#+(<0*$$1(F&(5&8#+G*<#(H*+5*A0#(<*&(A#(%$#?(8/(3/0?(+#G#+#&<#$(8/

/AD#<8$(/G(*&"(<0*$$(83*8(5>J0#>#&8$(83#(5&8#+G*<#1(`/83(83#(75+<0#(*&?(l#<8*&'0#(<0*$$#$(5>J0#>#&8(83#(F&5>*85/&

5&8#+G*<#(83+/%'3(83#5+($%J#+(<0*$$(.3*J#-($/(83#(+#G#+#&<#(8/(*(75+<0#(/+(l#<8*&'0#(/AD#<8(<*&(A#($8/+#?(5&(*&

Animation(H*+5*A0#1(;3#(;#c8(<0*$$(*0$/(5>J0#>#&8$(83#(F&5>*85/&(5&8#+G*<#-($/(83#(+#G#+#&<#$(8/(*(;#c8(/AD#<8(<*&

*0$/(A#($8/+#?(5&(*&(Animation(H*+5*A0#1

=&(83#(#c*>J0#(*A/H#-(H*+5*A0#(a(5$(/G(8"J#(Animation(O*&(5&8#+G*<#R1(=8(5$(G5+$8(*$$5'&#?(8/(83#(+#G#+#&<#(8/(*(75+<0#

/AD#<8-(83#&(*(l#<8*&'0#(/AD#<8-(*&?(0*$8(*(;#c8(/AD#<81(;3#(G/00/@5&'(5$(83#(/%8J%8(/G(83#(J+/'+*>1

.5&<#(75+<0#-(l#<8*&'0#-(*&?(;#c8(*00(5>J0#>#&8(F&5>*85/&-(@#(<*&($8/+#(83#(+#G#+#&<#$(8/(83#5+(/AD#<8$(5&(*&

F&5>*85/&(*++*"(*&?(J+/<#$$(83#>($"$8#>*85<*00"(5&(*(0//J(O$##(83#(</?#(A#0/@R1(V/+(*(J+/'+*>(83*8(>*&*'#$(*

0*+'#(&%>A#+(/G(/AD#<8$-(*A5058"(8/($8/+#(83#>(5&(*&(*++*"(*&?(J+/<#$$(83#>(@583(*(0//J(5&(*($"$8#>*85<(>*&&#+

@500(>*,#(J+/'+*>>5&'(>*&*'#*A0#1

Example 6: AnimateShapesTexts.java

publicpublic classclass AnimateShapesTexts

{

publicpublic staticstatic voidvoid main(String[] args)

{

Animation a;

a = newnew Circle("blue", truetrue, 30, 30, 5);

// center at (30, 30), radius 5

a.talk();

a.flipRight();

a.talk();

a = newnew Rectangle("orange", falsefalse, 50, 100, 30, 15);

// upper-left corner (50, 100), width 30, height

a.talk();

a.flipRight();

a.talk();

a = newnew Text("hello");

a.talk();

a.flipRight();

a.talk();

}

JAVA

I am Circle [@(30, 30), r: 5] [color=blue, filled=true]

I am Circle [@(40, 30), r: 5] [color=blue, filled=true]

I am Rectangle [@ (50, 100), w: 30, h: 15] [color=orange, filled=false]

I am Rectangle [@ (80, 100), w: 30, h: 15] [color=orange, filled=false]

I am Text [text=hello]

I am Text [text=olleh]

4/5/21, 10)50 PMIntermediate Programming

Page 65 of 185http://itec2150.gitlab.io/

;35$(J+/'+*>(3*$(#c*<80"(83#($*>#(/%8J%8(*$(83#(J+#H5/%$(J+/'+*>(83*8(?/#$(&/8(%$#(*(0//J1(;3#(J+/'+*>(<+#*8#$

*&(F&5>*85/&(*++*"(shapesAndTexts(@583($5a#(I1(b*<3(#0#>#&8(/G(83#(*++*"(<*&($8/+#(83#(+#G#+#&<#(8/(*&(/AD#<8(/G

*&"(<0*$$(83*8(5>J0#>#&8$(83#(F&5>*85/&(5&8#+G*<#1(;3#(+#G#+#&<#$(8/(*(75+<0#(/AD#<8-(*(l#<8*&'0#(/AD#<8-(*&?(*(;#c8

/AD#<8(*+#(*$$5'&#?(8/(#*<3(#0#>#&8(/G(83#(*++*"1(;3#(J+/'+*>(83#&(%$#$(*(G/+Q#*<3(0//J(8/(J+/<#$$(83#(*++*"1

70*$$#$(83*8(*+#(H#+"(?5GG#+#&8(G+/>(#*<3(/83#+(<*&(+#0*8#(8/(#*<3(/83#+(83+/%'3(83#(</>>/&(5&8#+G*<#(83#"

5>J0#>#&81(=8(5$(*$(5G(83*8(83#"(3*H#(*(</>>/&($%J#+(<0*$$1(=&8#+G*<#(>*,#$(58(H#+"(</&H#&5#&8(G/+(%$(8/(8*,#

*?H*&8*'#(/G(J/0">/+J35$>(8/($8/+#(H#+"(?5GG#+#&8(/AD#<8$(5&(*(?*8*($8+%<8%+#(O#1'1(*&(*++*"R(*&?(J+/<#$$(83#>(5&(*

$"$8#>*85<(>*&&#+1

3.6.3. Interface Inheritance

F&(5&8#+G*<#-(D%$8(05,#(*(<0*$$-(<*&(3*H#(*(J*+#&8(5&8#+G*<#1(;3*8(5$-(*&(5&8#+G*<#(<*&(#c8#&?(*(J*+#&8(5&8#+G*<#1(V/+

#c*>J0#-(83#(FullAnimation(5&8#+G*<#(A#0/@(5$(*(<350?(O$%AR(5&8#+G*<#(/G(83#(J*+#&8(O$%J#+R(5&8#+G*<#(Animation1

;3#(V%00F&5>*85/&(5&8#+G*<#(5&3#+58$(83#(8@/(*A$8+*<8(>#83/?$(O8*0,(*&?(G05Jl5'38R(G+/>(F&5>*85/&(*&?(*??$(83+##

&#@(*A$8+*<8(>#83/?$(G05JN#G8-(G05JZJ(*&?(G05J2/@&1

Example 7: FullAnimation.java

Example 7: Animation.java

publicpublic classclass AnimateShapesTextsLoop

{

publicpublic staticstatic voidvoid main(String[] args)

{

Animation[] shapesAndTexts = newnew Animation[3];

shapesAndTexts[0] = newnew Circle("blue", truetrue, 30, 30, 5);

// center at (30, 30), radius 5

shapesAndTexts[1] = newnew Rectangle("orange", falsefalse, 50, 100, 30, 15);

// upper-left corner (50, 100),

width 30, height 15

shapesAndTexts[2] = newnew Text("hello");

forfor (Animation a: shapesAndTexts)

{

a.talk();

a.flipRight();

a.talk();

System.out.println();

}

JAVA

publicpublic interfaceinterface FullAnimation extendsextends Animation

{

voidvoid flipLeft();

//flip to the left (mirror)

voidvoid flipUp();

//flip to the left (mirror)

voidvoid flipDown();

//flip to the left (mirror)

}

JAVA

The same as Animation.java in Example 6

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 66 of 185http://itec2150.gitlab.io/

4#(>/?5G5#?(83#(*A$8+*<8(<0*$$(.3*J#($/(83*8(58(5>J0#>#&8$(83#(V%00F&5>*85/&(5&$8#*?(/G(F&5>*85/&1(V+/>(83#(</?#

A#0/@-(@#(<*&($##(83*8(/&0"(83#(8*0,(>#83/?(5$(5>J0#>#&8#?-(83#(/83#+(G/%+(>#83/?$-(G05Jl5'38-(G05JN#G8-(G05JZJ-(*&?

G05J2/@&-(@500(A#(5>J0#>#&8#?(5&(83#(</&<+#8#($%A<0*$$#$(/G(.3*J#-(75+<0#(*&?(l#<8*&'0#1

Example 7: Shape.java

;3#(G/00/@5&'(5$(83#(ZSN(83*8(<*J8%+#$(83#(+#0*85/&$35J(*>/&'(83#(<0*$$#$(*&?(83#(5&8#+G*<#(5&(bc*>J0#(W1

publicpublic abstractabstract classclass Shape implementsimplements Comparable<Shape>, FullAnimation

{

privateprivate String color;

privateprivate booleanboolean filled;

publicpublic Shape(String color, booleanboolean filled)

{

supersuper();

thisthis.color = color;

thisthis.filled = filled;

}

//getters and setters for color and filled (not shown)

publicpublic abstractabstract doubledouble area();

@Override

publicpublic String toString()

{

returnreturn "[color=" + color + ", filled=" + filled + "]";

}

@Override

publicpublic intint compareTo(Shape o)

{

ifif (thisthis.area() > o.area())

returnreturn 1;

elseelse ifif (thisthis.area() < o.area())

returnreturn -1;

elseelse

returnreturn 0;

}

@Override

publicpublic voidvoid talk()

{

System.out.println("I am " + thisthis.toString());

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 67 of 185http://itec2150.gitlab.io/

.5&<#(83#(75+<0#(<0*$$(5$(*(&/&Q*A$8+*<8(<0*$$-(58(&##?$(8/(5>J0#>#&8(*00(83#(*A$8+*<8(>#83/?$(5&(V%00F&5>*85/&(A%8

&/8(5>J0#>#&8#?("#8(5&(.3*J#1

Example 7: Circle.java

4/5/21, 10)50 PMIntermediate Programming

Page 68 of 185http://itec2150.gitlab.io/

9/%(<*&(?/(*&(#cJ#+5>#&81(=G("/%(+#>/H#(83#(G05Jl5'38(>#83/?-(83#+#(@500(A#(*(</>J50#(#++/+1(;35$(D%$8(</&G5+>$

83*8(G05Jl5'38(5$(5&3#+58#?(A"(V%00F&5>*85/&(G+/>(F&5>*85/&(*&?(5$(J*+8(/G(83#(V%00F&5>*8/&(5&8#+G*<#1

;3#(G/00/@5&'(5$(83#(%J?*8#?(l#<8*&'0#(<0*$$B

Example 7: Rectangle.java

publicpublic classclass Circle extendsextends Shape

{

privateprivate intint x, y;

privateprivate intint radius;

publicpublic Circle(String color, booleanboolean filled, intint x, intint y, intint radius)

{

supersuper(color, filled);

thisthis.x = x; thisthis.y = y; thisthis.radius = radius;

}

//getters and setters for x, y, and radius

@Override

publicpublic String toString()

{

returnreturn "Circle [@(" + x + ", " + y + "), r: " + radius + "] " + supersuper.toString();

}

@Override

publicpublic doubledouble area()

{

returnreturn Math.PI * radius * radius;

}

@Override

publicpublic voidvoid flipRight()

{

x = x + 2 * radius;

}

@Override

publicpublic voidvoid flipLeft()

{

x = x - 2 * radius;

}

@Override

publicpublic voidvoid flipUp()

{

y = y - 2 * radius;

}

@Override

publicpublic voidvoid flipDown()

{

y = y + 2 * radius;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 69 of 185http://itec2150.gitlab.io/

;3#(G/00/@5&'(</?#(5$(H#+"($5>50*+(8/(*&(#c*>J0#(?#$<+5A#?(A#G/+#-(A%8(5&(*??585/&(8/(8*0,(*&?(G05J(+5'38-(#*<3($3*J#

<*&(*0$/(G05J(0#G8-(%J-(*&?(?/@&1

Example 7: AnimateShapes.java

publicpublic classclass Rectangle extendsextends Shape

{

privateprivate intint x, y;

privateprivate intint width, height;

publicpublic Rectangle(String color, booleanboolean filled, intint x, intint y, intint width, intint height)

{

supersuper(color, filled);

thisthis.x = x;

thisthis.y = y;

thisthis.width = width;

thisthis.height = height;

}

//getters and setters for x, y, width, and height (not shown)

@Override

publicpublic String toString()

{

returnreturn "Rectangle [@ (" + x + ", " + y + "), w: " + width + ", h: " + height + "] " +

supersuper.toString();

}

@Override

publicpublic doubledouble area()

{

returnreturn width*height;

}

@Override

publicpublic voidvoid flipRight()

{

x = x + width;

}

@Override

publicpublic voidvoid flipLeft()

{

x = x - width;

}

@Override

publicpublic voidvoid flipUp()

{

y = y - height;

}

@Override

publicpublic voidvoid flipDown()

{

y = y + height;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 70 of 185http://itec2150.gitlab.io/

;3#(G/00/@5&'(5$(83#(/%8J%8(/G(83#(J+/'+*>(*A/H#1(4#(<*&($##(83*8(5G(*($3*J#(G05J(+5'38(*&?(83#&(0#G8-(58(+#8%+&$(8/

83#(/+5'5&*0(0/<*85/&1(;3#($*>#(G/+(G05JJ5&'(%J(*&?(83#&(?/@&1

3.7. Summary

)/0">/+J35$>(<*&(A#(%$#?(8/(</&&#<8(?5GG#+#&8(<0*$$#$(83+/%'3(*(</>>/&($%J#+(<0*$$(/+(*(</>>/&(5&8#+G*<#(83#"

5>J0#>#&8-(*00/@5&'(/AD#<8$(A#0/&'5&'(8/(?5GG#+#&8(<0*$$#$(8/(A#($8/+#?(*&?(J+/<#$$#?($"$8#>*85<*00"1

3.8. Key Terms

publicpublic classclass AnimateShapes

{

publicpublic staticstatic voidvoid main(String[] args)

{

Shape[] shapes = newnew Shape[3];

shapes[0] = newnew Circle("blue", truetrue, 30, 30, 5);

// center at (30, 30), radius 5

shapes[1] = newnew Rectangle("orange", falsefalse, 50, 100, 30, 15);

// upper-left corner (50, 100), width 30,

height 15

shapes[2] = newnew Circle("red", falsefalse, 250, 250, 20);

// center at (250, 250), radius 20

forfor (Shape p: shapes)

{

p.talk();

p.flipRight();

p.talk();

p.flipLeft();

p.talk();

p.flipUp();

p.talk();

p.flipDown();

p.talk();

System.out.println();

}

JAVA

I am Circle [@(30, 30), r: 5] [color=blue, filled=true]

I am Circle [@(40, 30), r: 5] [color=blue, filled=true]

I am Circle [@(30, 30), r: 5] [color=blue, filled=true]

I am Circle [@(30, 20), r: 5] [color=blue, filled=true]

I am Circle [@(30, 30), r: 5] [color=blue, filled=true]

I am Rectangle [@ (50, 100), w: 30, h: 15] [color=orange, filled=false]

I am Rectangle [@ (80, 100), w: 30, h: 15] [color=orange, filled=false]

I am Rectangle [@ (50, 100), w: 30, h: 15] [color=orange, filled=false]

I am Rectangle [@ (50, 85), w: 30, h: 15] [color=orange, filled=false]

I am Rectangle [@ (50, 100), w: 30, h: 15] [color=orange, filled=false]

I am Circle [@(250, 250), r: 20] [color=red, filled=false]

I am Circle [@(290, 250), r: 20] [color=red, filled=false]

I am Circle [@(250, 250), r: 20] [color=red, filled=false]

I am Circle [@(250, 210), r: 20] [color=red, filled=false]

I am Circle [@(250, 250), r: 20] [color=red, filled=false]

4/5/21, 10)50 PMIntermediate Programming

Page 71 of 185http://itec2150.gitlab.io/

Dynamic BindingB(=&(?"&*>5<(A5&?5&'-(83#(>#83/?(<*00(5$(A/&?#?(8/(83#(>#83/?(A/?"(*8(+%&85>#1(;35$(5$(*0$/

,&/@&(*$(0*8#(A5&?5&'1

PolymorphismB()/0">/+J35$>(>#*&$(83*8(*(+#G#+#&<#(H*+5*A0#(<*&(3/0?(+#G#+#&<#$(8/(?5GG#+#&8(8"J#$(/G(/AD#<8$1

V/+(#c*>J0#-(*(+#G#+#&<#(H*+5*A0#(</%0?(+#G#+(8/(/AD#<8$(83*8(A#0/&'(8/(*&"(/G(58$($%A<0*$$#$1(F(+#G#+#&<#(H*+5*A0#

<*&(*0$/(3/0?(+#G#+#&<#$(8/(/AD#<8$(A#0/&'5&'(8/(?5GG#+#&8(<0*$$#$(83*8(5>J0#>#&8(83#($*>#(5&8#+G*<#1

Abstract MethodB(F&(*A$8+*<8(>#83/?(5$(*(>#83/?(83*8(5$(?#<0*+#?(A%8(</&8*5&$(&/(5>J0#>#&8*85/&1

Non-instantiableB(F(<0*$$(5$(&/&Q5&$8*&85*A0#(5G(/AD#<8$(/G(83*8(<0*$$(<*&(A#(<+#*8#?1

Abstract ClassB(F(<0*$$(83*8(</&8*5&$(*A$8+*<8(>#83/?$(5$(*&(*A$8+*<8(<0*$$1(;3#(<0*$$(3#*?#+(/G(*&(*A$8+*<8(<0*$$

&##?$(8/(</&8*5&(83#(,#"@/+?(*A$8+*<81(FA$8+*<8(<0*$$#$(>*"(&/8(A#(5&$8*&85*8#?(*&?(+#d%5+#($%A<0*$$#$(8/(J+/H5?#

5>J0#>#&8*85/&$(G/+(83#(*A$8+*<8(>#83/?$1

InterfaceB(F&(5&8#+G*<#(</&8*5&$(&/(*88+5A%8#$(A%8(/&0"(J%A05<(*A$8+*<8(>#83/?$1(F&(5&8#+G*<#(<*&&/8(A#

5&$8*&85*8#?1

Interface ImplementationB(F(<0*$$(5>J0#>#&8$(*&(5&8#+G*<#(A"(J+/H5?5&'(5>J0#>#&8*85/&$(/G(*8(0#*$8(/&#(/G(83#

*A$8+*<8(>#83/?$(</&8*5&#?(5&(83#(5&8#+G*<#1

Interface InheritanceB(;3#+#(5$(*0$/(5&3#+58*&<#(+#0*85/&$35J(*>/&'(5&8#+G*<#$-(D%$8(05,#(*>/&'(<0*$$#$1

Dynamic BindingB(=&(?"&*>5<(A5&?5&'-(83#(>#83/?(<*00(5$(A/&?#?(8/(83#(>#83/?(A/?"(*8(+%&85>#1(;35$(5$(*0$/

,&/@&(*$(0*8#(A5&?5&'1

PolymorphismB()/0">/+J35$>(>#*&$(83*8(*(+#G#+#&<#(H*+5*A0#(<*&(3/0?(+#G#+#&<#$(8/(?5GG#+#&8(8"J#$(/G(/AD#<8$1

V/+(#c*>J0#-(*(+#G#+#&<#(H*+5*A0#(</%0?(+#G#+(8/(/AD#<8$(83*8(A#0/&'(8/(*&"(/G(58$($%A<0*$$#$1(F(+#G#+#&<#(H*+5*A0#

<*&(*0$/(3/0?(+#G#+#&<#$(8/(/AD#<8$(A#0/&'5&'(8/(?5GG#+#&8(<0*$$#$(83*8(5>J0#>#&8(83#($*>#(5&8#+G*<#1

Abstract MethodB(F&(*A$8+*<8(>#83/?(5$(*(>#83/?(83*8(5$(?#<0*+#?-(A%8(</&8*5&$(&/(5>J0#>#&8*85/&1

Non-instantiableB(F(<0*$$(5$(&/&Q5&$8*&85*A0#(5G(/AD#<8$(/G(83*8(<0*$$(<*&(A#(<+#*8#?1

Abstract ClassB(F(<0*$$(83*8(</&8*5&$(*A$8+*<8(>#83/?$(5$(*&(*A$8+*<8(<0*$$1(;3#(<0*$$(3#*?#+(/G(*&(*A$8+*<8(<0*$$

&##?$(8/(</&8*5&(83#(,#"@/+?(*A$8+*$81(FA$8+*<8(<0*$$#$(>*"(&/8(A#(5&$8*&85*8#?-(*&?(+#d%5+#($%A<0*$$#$(8/(J+/H5?#

5>J0#>#&8*85/&$(G/+(83#(*A$8+*<8(>#83/?$1

InterfaceB(F&(5&8#+G*<#(</&8*5&$(&/(*88+5A%8#$(A%8(/&0"(J%A05<(*A$8+*<8(>#83/?$1(F&(5&8#+G*<#(<*&&/8(A#

5&$8*&85*8#?1

Interface ImplementationB(F(<0*$$(5>J0>#&8$(*&(5&8#+G*<#(A"(J+/H5?5&'(5>J0#>#&8*85/&$(/G(*8(0#*$8(/&#(/G(83#

*A$8+*<8(>#83/?$(</&8*5&#?(5&(83#(5&8#+G*<#1

Interface InheritanceB(;3#+#(5$(*0$/(5&3#+58*&<#(+#0*85/&$35J(*>/&'(5&8#+G*<#$-(D%$8(05,#(*>/&'(<0*$$#$1

4/5/21, 10)50 PMIntermediate Programming

Page 72 of 185http://itec2150.gitlab.io/

3.9. Exercises

3.9.1. Exercise 1

4+58#(*(J+/'+*>(8/($8/+#(83#(5&G/+>*85/&(G/+(*(&%>A#+(/G(?5GG#+#&8(G*+>(*&5>*0$(5&(*&(*++*"(/+(*++*"(05$8(*&?(83#&

?5$J0*"(83#($/%&?(83#(*&5>*0$(>*,#1

.%J#+70*$$(V*+>F&5>*0

F88+5A%8#$B(name-(gender-(weight-(*&?(age1

S#83/?$B

7/&$8+%<8/+

'#88#+$(*&?($#88#+$

sY8/.8+5&'(>#83/?(83*8(+#8%+&$(*($8+5&'(5&<0%?5&'(*00(*88+5A%8#$1

F&(*A$8+*<8(>#83/?(feedLoadingSchedule(83*8(?/#$(&/8(3*H#(*&"(J*+*>#8#+$(*&?(+#8%+&$(*($8+5&'1(=8

+#8%+&$(83#(85>#O$R(8/(0/*?(G##?$(#*<3(?*"1(=8(5$(A#88#+(G/+(835$(>#83/?(8/(A#(*A$8+*<8-($5&<#(/&0"(*(</&<+#8#

*&5>*0(8"J#(<*&(*<8%*00"(,&/@(83#(85>#O$R1

.%A<0*$$#$(735<,#&-(7/@-(2%<,1

F88+5A%8#$B(;3#"($3/%0?(#*<3(</&8*5&(*&(*88+5A%8#(sound1

S#83/?$B

b*<3(</&8*5&(*(</&$8+%<8/+(*&?('#88#+P$#88#+(>#83/?$1

UH#++5?#(83#(toString(>#83/?1

UH#++5?#(83#(feedLoadingSchedule(>#83/?1

!5&8B(V/+(A/83(83#(toString(*&?(feedLoadingSchedule(>#83/?$-(%$#(83#(/%8J%8(/G(83#(J+/'+*>(O$##

A#0/@R(8/(?#8#+>5&#(83#(G/+>*8(/G(83#($8+5&'(8/(+#8%+&1

FJJ05<*85/&B(4+58#(*(J+/'+*>(<*00#?(MyFarm1

7+#*8#(83#(G/00/@5&'($5c(/AD#<8$-($8/+#(83#>(5&(*(FarmAnimal(*++*"(/+(*++*"(05$81

)+5&8(/%8(83#5+(5&G/+>*85/&-(5&<0%?5&'(83#5+($/%&?$1

)+5&8(/%8(83#(G##?5&'($<3#?%0#(G/+(#*<3(*&5>*01

;3#(G/00/@5&'(5$(83#(/%8J%8(/G(83#(J+/'+*>1

4/5/21, 10)50 PMIntermediate Programming

Page 73 of 185http://itec2150.gitlab.io/

3.9.2. Exercise 2

4+58#(*(J+/'+*>(8/(J+/<#$$(?5GG#+#&8(/AD#<8$(83*8(<*&(G0"(5&(*($"$8#>*85<(>*&88#+(83+/%'3(83#($*>#(5&8#+G*<#(83#"

5>J0#>#&81

=&8#+G*<#(FlightB(7/&8*5&(/&0"(/&#(H/5?(>#83/?(G0"OR(O&/(J*+*>#8#+$R1

;@/(&/&Q*A$8+*<8(<0*$$#$(Airplane(*&?(Bird(83*8(5>J0#>#&8(83#(Flight(5&8#+G*<#1

Airplane(<0*$$B

;3+##(*88+5A%8#$B(>/?#0(*&?("#*+(A%508

Bird(<0*$$B

U&#(*88+5A%8#B(8"J#

`#$5?#$(83#(</&8+%<8/+$(*&?('#88#+$P$#88#+$-(A/83(83#(Airplane(*&?(Bird(<0*$$#$($3/%0?(5>J0>#&8(83#(fly(>#83/?1

;3#(F5+J0*&#m$(G0"(>#83/?($3/%0?(J+5&8(r=m>(*&(*5+J0*&#(83*8(+#05#$(/&(*&(#&'5&#(8/(G0"1r(;3#(`5+?m$(G0"(>#83/?

$3/%?(J+5&8(r=m>(*(A5+?(@3/(G0*J$(@5&'$(8/(G0"1r(b*<3($3/%0?(*0$/(5&<0%?#(*(toString()(>#83/?1

!5&8B(V/+(A/83(83#(toString(*&?(feedLoadingSchedule(>#83/?$-(%$#(83#(/%8J%8(/G(83#(J+/'+*>(O$##(A#0/@R(8/

?#8#+>5&#(83#(G/+>*8(/G(83#($8+5&'(8/(+#8%+&1

FJJ5<*85/&(J+/'+*>(ThingsThatFly

7+#*8#(/&#(Airplane(/AD#<8(*&?(8@/(Bird(/AD#<8$1(;3#(J+/'+*>(>%$8($8/+#(83#$#(/AD#<8$(5&(/&#(*++*"(/+(*++*"

05$81

;3#(J+/'+*>(>%$8(%$#(*(0//J(8/(J+5&8(83#(/AD#<8$(*&?(3/@(83#"(G0"1(9/%+(J+/'+*>($3/%0?(3*H#(83#(G/00/@5&'

/%8J%8B

3.9.3. Exercise 3

Duck Quack Quack [name=Donald, gender=male, weight=3.2, age=5]

Duck Quack Quack [name=Cheese, gender=female, weight=3.6, age=5]

Cow Moo Moo [name=Molly, gender=female, weight=1600.0, age=3]

Chicken Cock-a-Doodle-doo [name=Albert, gender=male, weight=1.6, age=2]

Chicken Cluck Cluck [name=Amelia, gender=female, weight=1.8, age=4]

Chicken Cluck Cluck [name=Dixie, gender=female, weight=1.7, age=4]

Donald: 8am-12pm-6pm

Cheese: 8am-12pm-6pm

Molly: 6am-4pm

Albert: 8am-4pm

Amelia: 8am-4pm

Dixie: 8am-4pm

Airplane [model=Boeing 747, year=2016]: I'm an airplane that relies on an engine to fly.

Bird [type=Eagle]: I'm a bird who flaps my wings to fly.

Bird [type=Hummingbird]: I'm a bird who flaps my wings to fly.

4/5/21, 10)50 PMIntermediate Programming

Page 74 of 185http://itec2150.gitlab.io/

;35$(#c#+<5$#(#c8#&?$(bc#+<5$#(E1(2#G5&#(*&/83#+(5&8#+G*<#(Movement(83*8(#c8#&?$(83#(5&8#+G*<#(Flight(G+/>

bc#+<5$#(E1(=8(</&8*5&$(8@/(&#@(*A$8+*<8(>#83/?$(walk()(*&?(jump()1(`/83(3*H#(&/(J*+*>#8#+$(*&?(&/(+#8%+&

H*0%#$1(j/@(>*,#(83#(Airplane(*&?(Bird(<0*$$#$(5>J0#>#&8(83#(Movement(5&8#+G*<#1(;3#(J+/'+*>(83*8(</&8*5&$

83#(>*5&(>#83/?($3/%0?(A#(<*00#?(*ThingsThatMoves1 ( =8 ( $3 / %0 ? (< + #* 8 #( 8 3# ( $* > #( / AD # <8 $ ( *$ ( 5& ( bc # +< 5 $# ( E( * &? ( $8 / +#

83#>(5&(*&(*++*"1(9/%+(J+/'+*>($3/%0?(3*H#(83#(G/00/@5&'(/%8J%8B

Airplane [model=Boeing 747, year=2016]:

I rely on my engine to fly.

I tax on my wheels.

I cannot jump.

Bird [type=Eagle]:

I flap my wings to fly.

I walk on my feet.

I jump by leaping from my feet.

Bird [type=Hummingbird]:

I flap my wings to fly.

I walk on my feet.

I jump by leaping from my feet.

4/5/21, 10)50 PMIntermediate Programming

Page 75 of 185http://itec2150.gitlab.io/

4. Exceptions

4.1. Learning Outcomes

2#$<+5A#(@3*8(*(6*H*(#c<#J85/&(5$(*&?(3/@(58(5$(%$#?(5&(/AD#<8Q/+5#&8#?(J+/'+*>>5&'

!*&?0#(6*H*(#c<#J85/&$(%$5&'(8+"P<*8<3($8*8#>#&8$

25GG#+#&85*8#(A#8@##&(3*&?05&'(*&(#c<#J85/&(*&?($5>J0"(r83+/@5&'r(/+(0#885&'(5$(3*JJ#&

2#$5'&(#GG#<85H#(#c<#J85/&(3*&?05&'

Z$#(*H*50*A0#(6*H*(bc<#J85/&(<0*$$#$(*H*50*A0#(5&(83#(6*H*(F)=

7+#*8#(*&?(%$#(*(<%$8/>(#c<#J85/&

4.2. Resources

4.2.1. Text and Tutorials

=&8+/?%<85/&(8/()+/'+*>>5&'(Z$5&'(6*H*Q(b5'383(b?585/&(A"(2*H5?(61(b<,B(73*J8#+([

O388JBPP>*8313@$1#?%PD*H*&/8#$P<[P5&?#c138>0R(73*J8#+([(Q(7/++#<8&#$$-(l/A%$8&#$$-(bGG5<5#&<"

6*H*-(6*H*-(6*H*B(UAD#<8QU+5#&8#?()+/A0#>(./0H5&'(AA"(l*0J3(S/+#005(*&?(l*0J3(4*0?#B

388JBPP@@@1<$18+5&</001#?%Pt+*>PDDDPDDDQ/$QETCWTMEL1J?G(73*J8#+(CT(bc<#J85/&$B(43#&(;35&'$(q/(4+/&'

U+*<0#(6*H*(;%8/+5*0(N#$$/&(/&(bc<#J85/&$B

388J$BPP?/<$1/+*<0#1</>PD*H*$#P8%8/+5*0P#$$#&85*0P#c<#J85/&$P5&?#c138>0

4.2.2. Videos

;3#(;3#/+"(/G(bc<#J85/&$(h5?#/(B(388J$BPP@@@1"/%8%A#1</>P@*8<3\H][4;hN*Cu8$,

)+*<85<*0(Z$#(/G(bc<#J85/&$(h5?#/B(388J$BPP@@@1"/%8%A#1</>P@*8<3\H]l+_>@N`bHQZk8]ET$

F&/83#+(bc<#J85/&$(h5?#/B(388J$BPP@@@1"/%8%A#1</>P@*8<3\H]_YQIUN,u,a9

4.3. Overview

43#&(+%&&5&'("/%+(J+/'+*>-(58(5$(&/8(%&</>>/&(8/(+%&(5&8/(J+/A0#>$(@35<3(<*%$#(83#(J+/'+*>(8/(8#+>5&*8#(/+

$8/J(+%&&5&'1(43#&(83#$#(8"J#$(/G(#++/+$(*+#(?#8#<8#?(5&(6*H*(J+/'+*>$-(83#(+%&Q85>#(#&H5+/&>#&8(<+#*8#$(*&

/AD#<8(,&/@&(*$(*&(exception1(F&/83#+(?#G5&585/&(G/+(*&(#c<#J85/&(5$(*(+%&Q85>#(#++/+(83*8(<*%$#$(*(J+/'+*>(8/

<+*$31(;3#(&*>#(*0$/(5>J05#$(83*8(58(5$(*($58%*85/&(83*8(5$(&/8(&/+>*0(#c#<%85/&1(;3#(6*H*(F)=(</&8*5&$(*($#8(/G

<0*$$#$(%$#?(*$(8#>J0*8#$(G/+(83#(/AD#<8$(<+#*8#?(@3#&(83#(#++/+$(*+#(?#8#<8#?1(=&(83#(J*<,*'#(D*H*10*&'-(83#$#

<0*$$#$(*+#($/>#85>#$(<*00#?(83#(#c<#J85/&(<0*$$#$1(=&(*&(5?#*0(@/+0?-(&/(J+/'+*>(@/%0?(#&</%&8#+(#c<#J85/&$1

!/@#H#+-(@#(?/&m8(05H#(5&(*&(5?#*0(@/+0?($/(83#(6*H*(0*&'%*'#(</&8*5&$($8*8#>#&8$(*&?(</&$8+%<8$(83*8(*00/@(%$(8/

r3*&?0#r(#c<#J85/&$(@3#&(83#"(/<<%+1(!*&?05&'(*&(#c<#J85/&(>#*&$(83*8(83#(J+/'+*>(</&8*5&$(</?#(8/(#583#+

</++#<8(*&(#c<#J85/&(/+(J+/H5?#(*&(*08#+&*85H#(8/(*00/@5&'(83#(J+/'+*>(8/(<+*$31(bc<#J85/&$(<*&(A#(<*%$#?(A"

#++/+$('#&#+*8#?(A"(#c8#+&*0(5&J%8$(/+($5>J0"(*(A*?(J+/'+*>(?#$5'&1(6*H*(%$#$(83#(8#+>(r83+/@r(8/(?#$<+5A#(@3*8

3*JJ#&$(@3#&(*&(#c<#J85/&(/<<%+$1(;3#(+%&Q85>#(#&H5+/&>#&8(5$($*5?(8/(83+/@(*&(#c<#J85/&(@3#&(58(/<<%+$1(43*8

5$(*<8%*00"(3*JJ#&5&'(5$(83*8(83#(+%&Q85>#(#&H5+/&>#&8(5$('*83#+5&'(5&G/+>*85/&(*A/%8(83#(8"J#(/G(#++/+(83*8

4/5/21, 10)50 PMIntermediate Programming

Page 76 of 185http://itec2150.gitlab.io/

/<<%++#?(*&?(83#(05&#(*8(@35<3(58(/<<%++#?(*&?($8/+5&'(83*8(5&G/+>*85/&(5&8/(*&(/AD#<8(83*8(5$(?#+5H#?(G+/>(83#(6*H*

#c<#J85/&(<0*$$#$1(;3#(J+/'+*>>#+(<*&(*0$/(5&<0%?#(</?#(@35<3(*00/@$(G/+(*&(#c<#J85/&(8/(A#(83+/@&(A"(83#

J+/'+*>(58$#0G(%&?#+(<#+8*5&(<5+<%>$8*&<#$1(F&(%&3*&?0#?(#c<#J85/&(@500(<*%$#(83#(+%&&5&'(J+/'+*>>5&'(8/

8#+>5&*8#(*&?(J+5&8(*($8*<,(8+*<#1(;/(3#0J(J+#H#&8(835$-(83#(J+/'+*>>#+(<*&(5&<0%?#(8+"P<*8<3(A0/<,$(@35<3(*00/@

83#(J+/'+*>>#+(8/(J+/H5?#(*&(*08#+&*8#(<3/5<#(8/(#&?5&'(83#(J+/'+*>1(;35$(5$(,&/@&(*$(r3*&?05&'r(83#(#c<#J85/&1

=&(*??585/&-(58(5$(J/$$5A0#(8/(@+58#(</?#(@35<3(<+#*8#$-(83+/@$(*&?(3*&?0#$(<%$8/>(#c<#J85/&$(@35<3(5&3#+58(G+/>

83#(F)=(J+/H5?#?(#c<#J85/&(<0*$$#$1(;35$(<3*J8#+(?#$<+5A#$(</>>/&(6*H*(F)=(#c<#J85/&$-(3/@(8/(J+/'+*>>*85<*00"

83+/@(#c<#J85/&$-(3/@(8/(3*&?0#(#c<#J85/&$(*&?(3/@(8/(<+#*8#("/%+(/@&(<%$8/>5a#?(#c<#J85/&$1

4.4. Exception Handling

;3#(5?#*(/G(3*&?05&'(J+/A0#>$(?%+5&'(#c#<%85/&(3*$(A##&(*(J*+8(/G(J+/'+*>>5&'($5&<#(83#+#(3*$(A##&

J+/'+*>>5&'1(!/@#H#+-(6*H*(@*$(/&#(/G(83#(G5+$8(0*&'%*'#$(8/(J+/H5?#($J#<5*0($8*8#>#&8$(G/+(83#(3*&?05&'(/G(83#$#

#c<#J85/&*0(J+/A0#>$1(./>#(</>>/&(#++/+$(83*8('#&#+*8#(#c<#J85/&$(*+#(?5H5?#(A"(a#+/(#++/+$(*&?(*++*"(5&?#c

/%8(/G(A/%&?$1(F(J$#%?/</?#($/0%85/&(8/(J+#H#&8(835$(#++/+(@583/%8($J#<5*0($8*8#>#&8$(5$($3/@&(A#0/@1

*Divide by Zero Exception Handling Pseudo Code*

if (denominator not equal to 0)

answer = numerator/denominator;

else

inform user that division is not possible due to divide by zero

;35$(8+*?585/&*0(*JJ+/*<3(5&</+J/+*8#$(83#(3*&?05&'(/G(83#(#++/+(5&8/(83#(&/+>*0(#c#<%85/&(/G(83#(</?#1(6*H*(3*$

5&</+J/+*8#?(*&(#c<#J85/&Q3*&?05&'(>/?#0(5&8/(83#(</?#(58$#0G1(=&(83#(<*$#(/G(*(?5H5?#QA"Qa#+/(#++/+(/<<%++5&'

@583/%8(#c<#J85/&(3*&?05&'(</?#-(83#(+%&Q85>#(#&H5+/&>#&8(?#8#<8$(83#(#++/+(*&?(*A/+8$(83#(J+/'+*>1(;3#&(58

J+5&8$(*($8*<,(8+*<#1(F&(#c*>J0#($8*<,(8+*<#(G/+(*(?5H5?#QA"Qa#+/(#++/+(5$($3/@&(A#0/@1

java.lang.ArithmeticException: / by zero

at DivideException.main(DivideException.java:10)

F$("/%(<*&($##-(83#($8*<,(8+*<#(G5+$8(?#$<+5A#$(83#(#c<#J85/&(83*8(/<<%+$(*&?(83#&(05$8$(83#(<*00($8*<,(#&?5&'(@583(83#

05&#(&%>A#+(*&?(>#83/?(&*>#(@3#+#(83#(#c<#J85/&(/<<%+$1(=&(835$(<*$#-(83#(#++/+(/<<%++#?(5&(83#(>*5&(>#83/?(/G

83#(D*H*(G50#(25H5?#bc<#J85/&1D*H*(/&(05&#(CT1(;3#($8*<,(8+*<#(5$(5&8#&?#?(8/(3#0J(83#(J+/'+*>>#+(?#A%'(83#

J+/A0#>(*&?(5$(&/8(</&$5?#+#?(*(H#+"('//?(#++/+(>#$$*'#(G/+(*(<*$%*0(%$#+1

;3#(*<8(/G(?#8#<85&'(83#(#++/+(*&?(<*%$5&'(83#(J+/'+*>(8/(*A/+8(A"(?#G*%08(5$(,&/@&(*$(r83+/@5&'r(83#(#c<#J85/&1

;3#(#c<#J85/&($3/@&(Q(D*H*10*&'1F+583>#85<bc<#J85/&(Q(5$(/&#(/G(>*&"(J+/H5?#?(5&(83#(6*H*(F)=1(b*<3(#c<#J85/&(5$(*

<0*$$(5&(83#(6*H*(05A+*+"1(;3#(?5*'+*>(A#0/@($3/@$(*(ZSN(?5*'+*>(/G(83#(#c<#J85/&(<0*$$#$(5&(83#(6*H*(05A+*+"1(F$

"/%(<*&($##(5&(83#(?5*'+*>-(*00(83#(bc<#J85/&$(5&3#+58(G+/>(83#(<0*$$(;3+/@*A0#1

Exception Hierarchy

4/5/21, 10)50 PMIntermediate Programming

Page 77 of 185http://itec2150.gitlab.io/

4.5. Checked Exception vs UnChecked Exception

;3#(#c<#J85/&(<0*$$#$(*+#(?5H5?#?(5&8/(<3#<,#?(*&?(%&<3#<,#?(#c<#J85/&$1(;3#(%&<3#<,#?(#c<#J85/&$(5&3#+58(G+/>

83#(<0*$$(l%&;5>#bc<#J85/&1(Z&<3#<,#?(>#*&$(83*8(83#(</>J50#+(@500(&/8(+#d%5+#(#c<#J85/&(3*&?05&'(</?#(*+/%&?

*($8*8#>#&8(83*8(3*$(83#(J/8#&85*0(8/(83+/@&(*&(#c<#J85/&1(25H5?#(A"(a#+/(5$(*&(#c*>J0#(/G(*&(%&<3#<,#?

#c<#J85/&1(=G(58(@#+#(<3#<,#?-(#H#+"(?5H5$5/&($8*8#>#&8(@/%0?(&##?(8/(3*H#(#c<#J85/&(3*&?05&'(</?#1(Z&<3#<,#?

#c<#J85/&$(*+#(8"J5<*00"(</&?585/&$(83*8(83#(J+/'+*>(<*&(&/8(*&85<5J*8#(/+(+#</H#+(G+/>1(S*&"(/G(83#$#(*+#

5&?5<*85/&$(/G(*(0/'5<(#++/+(5&(83#(</?#(83*8($3/%0?(A#(</++#<8#?(A"(<3*&'5&'(83#(</?#1(V/+(#c*>J0#-(J*$$5&'(*&

/AD#<8(+#G#+#&<#(H*+5*A0#(8/(*(>#83/?(A#G/+#(58(5$(5&585*05a#?(@500(+#$%08(5&(*(j%00)/5&8#+bc<#J85/&(A#5&'('#&#+*8#?1

;3#(J+/'+*>>#+($3/%0?(>*,#($%+#(83*8(83#(+#G#+#&<#(H*+5*A0#(5$(5&85*05a#?(A#G/+#(%$5&'(581(73#<,#?(#c<#J85/&$(*+#

</&?585/&$(83*8(*(@#00Q@+588#&(J+/'+*>($3/%0?(*&85<5J*8#(*&?(J0*&(G/+1(S*&"(/G(83#(<3#<,#?(#c<#J85/&$(5&H/0H#(G50#

J+/<#$$5&'(*&?(*+#(%$#?(J+/>5&*&80"(5&(83#(&#c8(<3*J8#+(/&(G50#(J+/<#$$5&'1(F(<*00(8/(*(>#83/?(83*8(5$(<*J*A0#(/G

83+/@5&'(*&(#c<#J85/&$(@500(+#<#5H#(</>J50#+(#++/+$(5G(58(?/#$(&/8(%$#(#c<#J85/&(3*&?05&'(</?#1(7%$8/>(?#$5'&#?

#c<#J85/&(<*&(A#(#583#+(<3#<,#?(/+(%&<3#<,#?(?#J#&?5&'(%J/&(@35<3(J*+#&8(#c<#J85/&(<0*$$(83#"(5&3#+58(G+/>1

4.6. Try/Catch/Finally Blocks

bc<#J85/&(3*&?05&'(</?#(<*&(A#(0//,#?(*8(*$(3*H5&'(83+##(8"J#$(/G(/J#+*85/&$1(s2#<0*+5&'(*&(#c<#J85/&(s;3+/@5&'

*&(#c<#J85/&(s7*8<35&'(*&(#c<#J85/&

4.6.1. Declaring an exception

F00(#c#<%8*A0#(</?#(5&(6*H*(A#0/&'$(8/(*(>#83/?1(=G(*(>#83/?(5$(<*J*A0#(/G(83+/@5&'(*(<3#<,#?(#c<#J85/&-(58

</&8*5&$(*(throws($8*8#>#&8(5&(58$(3#*?#+1(V/+(#c*>J0#-(*(>#83/?(@35<3(83+/@$(*&(/AD#<8(/G(8"J#(=Ubc<#J85/&

@/%0?(0//,(05,#(835$B(public void aMethod(int a) throws IOException

;35$(?/#$(&/8(>#*&(83#(*S#83/?(@500(*0@*"$(83+/@(*&(IOException-(58(>#*&$(83*8(83#(>#83/?(5$(<*J*A0#(/G(?/5&'

$/1

4.6.2. Throwing an exception

4/5/21, 10)50 PMIntermediate Programming

Page 78 of 185http://itec2150.gitlab.io/

=&(/+?#+(G/+(83*8(#++/+(8/(A#(83+/@&-(83#+#(>%$8(A#(</?#(#583#+(5&(*S#83/?(/+(/&#(/G(83#(>#83/?$(58(<*00$(83*8

?#8#<8$(*&(#++/+-(<+#*8#$(83#(#c<#J85/&(/AD#<8(*&?(83#&(83+/@$(83#(#c<#J85/&1(.%JJ/$#(83*8(83#(J+/'+*>(?#8#<8$

83*8(*&(*+'%>#&8(J*$$#?(8/(83#(>#83/?(5$(/G(5&</++#<8(8"J#(/+(H5/0*8#$(83#(>#83/?(</&8+*<8(O*(&#'*85H#(H*0%#

+#<#5H#?(@3#&(*(J/$585H#(/&#(5$(#cJ#<8#?R1(=8(</%0?(83#&(83+/@(*&(=00#'*0F+'%>#&8bc<#J85/&(/AD#<81(;3#(</?#

A#0/@$($3/@(3/@(83#(#c<#J85/&(5$(<+#*8#?(*&?(83+/@&1(;3#(</?#($3/@&(*$$%>#$(83*8(83#(<0*$$

java.lang.IllegaalArgumentException(3*$(A##&(J+/J#+0"(5>J/+8#?(5&8/(83#(6*H*(G50#(</&8*5&5&'(83#(</?#1

;5JB(;3#(,#"@/+?(8/(?#<0*+#(*&(#c<#J85/&(5$(throws(*&?(83#(,#"@/+?(8/(83+/@(*&(#c<#J85/&(5$(throw1(;3#$#(*+#

$5>50*+-(A%8(?/(?5GG#+#&8(835&'$1

4.6.3. Catching an exception

=G(*(J+/'+*>>#+(?/#$(&/8(@*&8(83#(#c<#J85/&(8/(8#+>5&*8#(83#(J+/'+*>-(*8($/>#(J/5&8(83#(#c<#J85/&(>%$8(A#

<*%'38(5&(*(try-catch(A0/<,1(;3#(try-catch(A0/<,(*00/@$(83#(J+/'+*>>#+(8/($#J*+*8#(83#(</?#(83*8(#c#<%8#$(@3#&

&/(#c<#J85/&(/<<%+$(G+/>(83#(#++/+(3*&?05&'(</?#1(;3#(try(A0/<,(</&8*5&$(83#(?#$5+#?(#c#<%85/&(/G(83#(</?#1(;3#

catch(A0/<,(</&8*5&$(83#(</?#(8/(3*&?0#(*&(#++/+(5G(*&?(@3#&(58(/<<%+$1(=G(&/(#c<#J85/&$(/<<%+(?%+5&'(83#(#c#<%85/&

/G(83#(try(A0/<,-(83#(catch(A0/<,(</?#(5$(5'&/+#?1

;3#(</?#(@5835&(83#(<*8<3(A0/<,(/+(A0/<,$(5$(83#(#c<#J85/&(3*&?05&'(</?#1(=G(&/(3*&?0#+(#c5$8$(G/+(83#(#c<#J85/&(83*8

/<<%+$-(83#(#c<#J85/&(@500(+#$%08(5&(83#(J+/'+*>(8#+>5&*85&'1(=&(83#(#c*>J0#(*A/H#-(83#+#(*+#(8@/(<*8<3(A0/<,$(G/+

83#($5&'0#(8+"(A0/<,1(."&8*c(/&0"(+#d%5+#$(/&#(<*8<3(A0/<,-(A%8(58(5$(/G8#&(%$#G%0(8/(A#(*A0#(8/(?/(?5GG#+#&8(835&'$(G/+

?5GG#+#&8(8"J#$(/G(#c<#J85/&$1(=8(5$(*0$/(J/$$5A0#(8/(%$#(5&3#+58*&<#(8/(<*8<3(>%085J0#(#c<#J85/&$(5&(*($5&'0#(<*8<3

A0/<,1

IllegalArgumentException ex = new IllegalArgumentException("Negative argument received");

throw ex;

trytry{

// code that could potentially thrown an exception

}

catchcatch (NullPointerException e)

{

// code that is called if a NullPointerException occurs in the code encased in the try block

}

catchcatch (ArithmeticException e2)

{

// code that is called if an ArithmeticException occurs in the code encased in the try block

}

JAVA

trytry

{

// code that could potentially throw an exception

}

catchcatch (Exception ex)

{

// this will catch any exception thrown by the program since all Exception types inherit from the parent

class named Exception.

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 79 of 185http://itec2150.gitlab.io/

=G(%$5&'(>%085J0#(<*8<3(A0/<,$Q(A#($%+#(83#(>/+#('#&#+*0(bc<#J85/&(<0*$$(5$(0*$81

F&(#c<#J85/&(/AD#<8(</&8*5&$(H*0%*A0#(5&G/+>*85/&(*A/%8(@3*8(3*JJ#&#?(8/(<*%$#(581(F00(#c<#J85/&$(5&3#+58(83#

G/00/@5&'(>#83/?$(G+/>(83#(J*+#&8(<0*$$(;3+/@*A0#1

F($8*<,(8+*<#(5$($/>#85>#$(<*00#?(*($8*<,(A*<,8+*<#(/+(#H#&(D%$8(*(A*<,8+*<#1(;3#($8*<,(8+*<#5$(*(05$8(/G($8*<,(G+*>#$1

F($8*<,(G+*>#(5&?5<*8#$(*(>/>#&8(?%+5&'(*&(*JJ05<*85/&m$(#c#<%85/&(@3#&(*(>#83/?(5$(<*00#?1(F($8*<,(G+*>#

</&8*5&$(5&G/+>*85/&(*A/%8(@3#+#(83#(>#83/?(@*$(<*00#?(G+/>(5&(83#(6*H*($/%+<#(</?#1(./(83#(6*H*($8*<,(8+*<#

'#&#+*8#?(@3#&(*&(#c<#J85/&(5$(<*00#?(5$(*(05$8(/G(G+*>#$(83*8($8*+8$(*8(05&#(5&(83#(>#83/?(83#(#c<#J85/&(/<<%++#?

*&?(#c8#&?$(A*<,(8/(@3#&(83#(J+/'+*>($8*+8#?1(4350#(&/8(J*+85<%0*+0"(%$#G%0(8/(J+/'+*>(%$#+-(58(J+/H5?#$(H*0%*A0#

5&G/+>*85/&(8/(83#(J+/'+*>>#+(*A/%8(@3#+#(83#(#c<#J85/&(/<<%++#?1

4.7. Handling Exception vs Throwing Exception

43#&(*(>#83/?(83+/@$(*(<3#<,#?(#c<#J85/&(/+(<*00$(*&/83#+(>#83/?(83*8(?/#$-(83#(</>J50#+(@500(&/8(</>J50#(83#

</?#(%&0#$$(83#(#c<#J85/&(5$(#583#+(83+/@&(/+(3*&?0#?1(;/(3*&?0#(83#(#c<#J85/&-(83#(>#83/?(>%$8(</&8*5&(*

8+"P<*8<3(A0/<,(*$(?#$<+5A#?(5&(83#(J+#H5/%$($#<85/&1(;3+/@5&'(*&(#c<#J85/&(J*$$#$(83#(A%+?#&(/G(3*&?05&'(58(8/(83#

// wrong way to do it

trytry

{

// code

}

catchcatch (Exception ex)

{

// this block will catch all exceptions since all handlable exception inherit from Exception

}

catchcatch (NullPointerException e)

{

// a waste of code- this will never be called because the NullPointerException inherits from Exception

}

JAVA

// right way

trytry

{

// code

}

catchcatch (NullPointerException e)

{

// This will handle any NullPointerExceptions

}

catchcatch (Exception ex)

{

// this block will catch any other exceptions that occur - order matters

}

JAVA

String getMessage() - this method returns a string identifying the type of exception that occurred.

void printStackTrace() - this method prints current stack trace to the console and the type of exception thrown.

4/5/21, 10)50 PMIntermediate Programming

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<*005&'(>#83/?1(=G(835$(5$(83#(>*5&OR(>#83/?-(83#+#(5$(&/(<*005&'(>#83/?(*&?(83#(#c<#J85/&(<*%$#$(J+/'+*>

8#+>5&*85/&1(;/(83+/@(*&(#c<#J85/&-(83#(>#83/?(>%$8(%$#(83#(,#"(@/+?(throws(5&(83#(>#83/?(3#*?#+1

4.8. Custom Exceptions

=8(5$(J/$$5A0#(8/(<+#*8#(*&?(83+/@(<%$8/>5a#?(#c<#J85/&$(G/+(*(J+/'+*>1(;/(?/(835$-(83#(G5+$8($8#J(5$(8/(<+#*8#(83#

<%$8/>(#c<#J85/&1(F&(#c<#J85/&(5$(*(6*H*(<0*$$(*&?(58(>%$8(5&3#+58(G+/>(/&#(/G(83#(#c5$85&'(6*H*(bc<#J85/&(<0*$$#$

G+/>(83#(6*H*(F)=1

U&<#(83#(<%$8/>(#c<#J85/&(<0*$$(5$(<+#*8#?(*&?(</>J50#?-("/%+(J+/'+*>(<*&(83#&(#cJ05<580"(<*%$#(83*8(#c<#J85/&(8/

3*JJ#&1

4.9. An example of Exception Handling used to validate input from user

F(</>>/&(%$#(/G(#c<#J85/&(3*&?05&'(5$(8/(>*,#($%+#(83*8(83#(%$#+(#&8#+$(83#(8"J#(/G(?*8*(?#$5+#?(@3#&(+#*?5&'

G+/>(83#(</&$/0#1(43#&(%$5&'(.<*&&#+(/AD#<8$(8/(+#*?(%$#+(5&J%8-(*(.8+5&'(5&J%8(@3#&(+#d%#$85&'(*(&%>#+5<(5&J%8

<*&('#&#+*8#(*&(=&J%8S5$>*8<3bc<#J85/&(<*%$5&'(83#(J+/'+*>(8/(*A+%J80"(8#+>5&*8#1(bc<#J85/&(3*&?05&'(<*&

J+#H#&8(83#(8#+>5&*85/&(*&?(*00/@(83#(%$#+(8/(8+"(*'*5&1(;3#(G/00/@5&'(#c*>J0#(*$,$(83#(%$#+(8/(#&8#+(K(&%>A#+$

*&?(83#&(</>J%8#$(83#(*H#+*'#1(;3#(G5+$8(H#+$5/&(3*$(&/(#c<#J85/&(3*&?05&'(*&?(5G(*(0#88#+(5$(#&8#+#?(5&$8#*?(/G(*

&%>A#+Q(83#(J+/'+*>(@500(83+/@(*&(#c<#J85/&(*&?(8#+>5&*8#Q(?/@&0/*?(58(*&?(8+"n

publicpublic intint someMethod() throwsthrows IOException

{

// code that can cause an IOException to occur

}

JAVA

// A custom Exception class

// CustomException.java

public class CustomException extends Exception

{

// custom exceptions must include a constructor that has a single parameter of type String.

public CustomException(String s)

{

// this constructor must call the parent class constructor

super(s)

}

publicpublic voidvoid someMethod() throwsthrows CustomException

{

// some code

ifif (bad thing happens)

{

// note that you throw an object of CustomException - not the class so an object must be created.

throwthrow newnew CustomException("A bad thing happened");

}

// some more code that only executes if the bad thing didnt happen

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 81 of 185http://itec2150.gitlab.io/

j/@(0#8(%$(0//,(*8(*&(#c*>J0#(@583(#c<#J85/&(3*&?05&'(83*8($5>J0"(5'&/+#$(83#(#c<#J85/&1

/**

* This class prompts the user for four numbers and then

* computes the average and prints it.

importimport java.util.Scannerjava.util.Scanner;

publicpublic classclass AverageCalculator

{

publicpublic staticstatic voidvoid main(String[] args)

{

// declare variables

Scanner consoleInput = newnew Scanner(System.in);

doubledouble[] x = newnew doubledouble[4];

doubledouble average = 0;

doubledouble sum = 0;

// input numbers

forfor (intint i = 0; i < 4; i++)

{

System.out.println("Enter number " + (i + 1) + ":");

x[i] = consoleInput.nextDouble();

sum = sum + x[i];

}

// compute average

average = sum / 4.0;

// output average to console

System.out.println("The average is " + average);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 82 of 185http://itec2150.gitlab.io/

;3#(J+/A0#>(@583(5'&/+5&'(83#(A*?(5&J%8(5$(83*8(83#(%$#+(?/#$(&/8('#8(*(<3*&<#(8/(+##&8#+(83#(</++#<8(H*0%#1(;3*8

H*0%#(5$(J+#$#8(8/(T(*&?($,#@$(83#(*H#+*'#1(N#8m$(0//,(*8(*(835+?(H#+$5/&(83*8(J+/>J8$(83#(%$#+(8/(+##&8#+(83#

>5$8"J#?(H*0%#1

/**

* This class prompts the user for four numbers and then

* computes the average and prints it.

importimport java.util.InputMismatchExceptionjava.util.InputMismatchException;

importimport java.util.Scannerjava.util.Scanner;

publicpublic classclass AverageCalculatorIgnore

{

publicpublic staticstatic voidvoid main(String[] args)

{

// declare variables

Scanner consoleInput = newnew Scanner(System.in);

doubledouble[] x = newnew doubledouble[4];

doubledouble average = 0;

doubledouble sum = 0;

// input numbers

forfor (intint i = 0; i < 4; i++)

{

trytry

{

System.out.println("Enter number " + (i + 1) + ":");

x[i] = consoleInput.nextDouble();

sum = sum + x[i];

} catchcatch (InputMismatchException ex)

{

// ignore the error by reading the lingering delimiter

consoleInput.nextLine();

}

// compute average

average = sum / 4.0;

// output average to console

System.out.println("The average is " + average);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 83 of 185http://itec2150.gitlab.io/

j/8#(83*8(*00(/G(83#(H*+5*A0#$(%$#?(*+#(?#<0*+#?(A#G/+#(83#(8+"P<*8<3(A0/<,1(;35$(5$(A#<*%$#(*&"(H*+5*A0#(?#<0*+#?(5&

83#(8+"(A0/<,(5$(/&0"(%$*A0#(5&(83#(<%+0"(A+*<#$($%++/%&?5&'(83#(8+"(</?#(?%#(8/(H*+5*A0#($</J#1(43#&(%$5&'

#c<#J85/&(3*&?05&'-(>*,#($%+#(*00(H*+5*A0#$(*+#(?#<0*+#?(A#G/+#(83#(8+"P<*8<3(A0/<,1

4.10. Summary

/**

* This class prompts the user for four numbers and then

* computes the average and prints it.

importimport java.util.InputMismatchExceptionjava.util.InputMismatchException;

importimport java.util.Scannerjava.util.Scanner;

publicpublic classclass AverageCalculatorHandle

{

publicpublic staticstatic voidvoid main(String[] args)

{

// declare variables

Scanner consoleInput = newnew Scanner(System.in);

doubledouble[] x = newnew doubledouble[4];

doubledouble average = 0;

doubledouble sum = 0;

// input numbers

forfor (intint i = 0; i < 4; i++)

{

booleanboolean goodValueReceived = falsefalse;

whilewhile (!goodValueReceived)

{

trytry

{

System.out.println("Enter number " + (i + 1) + ":");

x[i] = consoleInput.nextDouble();

sum = sum + x[i];

goodValueReceived = truetrue;

} catchcatch (InputMismatchException ex)

{

// read in the bad value

consoleInput.nextLine();

System.out.println("Sorry- that wasn't a number -try again");

}

// compute average

average = sum / 4.0;

// output average to console

System.out.println("The average is " + average);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 84 of 185http://itec2150.gitlab.io/

bc<#J85/&$(5&(6*H*(J+/'+*>$(/<<%+(@3#&(*(+%&Q85>#(#++/+(/<<%+$(83*8(83#(6lb(<*&(&/8(+#</H#+(G+/>1

F(6*H*(bc<#J85/&(5$(*&(5&$8*&<#(/G(<0*$$(?#+5H#?(G+/>(D*H*10*&'1;3+/@*A0#

43#&(*(+%&Q85>#(#++/+(/<<%+$(83*8(<*%$#$(*&(bc<#J85/&(<0*$$(8/(A#(5&$8*&85*8#?(*&?(5&8#++%J8(83#(J+/'+*>

#c#<%85/&-(@#($*"(83*8(83#(#c<#J85/&(@*$(thrown

bc<#J85/&$(<*&(A#(#583#+(<3#<,#?(/+(%&<3#<,#?

73#<,#?(#c<#J85/&$(>#*&(83#(</>J50#+(+#d%5+#$(83#(J+/'+*>>#+(8/(*<,&/@0#?'#(83#(J/$$5A5058"(/G(83#

#c<#J85/&(83+/%'3(83#(%$#(/G(*(8+"P<*8<3(A0/<,(8/(3*&?0#(58(/+(*(83+/@$(<0*%$#(/&(83#(>#83/?(5&?5<*85&'(83*8

3*&?05&'(83#(#c<#J85/&(5$(A#5&'(J*$$#?(8/(83#(<*005&'(>#83/?

;3#(</>J50#+(?/#$(&/8(+#d%5+#(83*8(J+/'+*>>#+$(*<,&/@0#?'#(%&<3#<,#?(#c<#J85/&(J/$$5A5058"1

;+"P<*8<3(A0/<,$(*00/@(83#(%$#+(8/(3*&?0#(*&(#c<#J85/&(+*83#+(83*&($5>J0"(0#885&'(58(#&?(83#(J+/'+*>

7%$8/>(#c<#J85/&$(<*&(A#(<+#*8#?(83*8(5&3#+58(G+/>(#c5$85&'(05A+*+"(bc<#J85/&(<0*$$#$1

4.11. Key Terms

bc<#J85/&(Q(F&(#++/&#/%$(/+(*&/>*0/%$(</&?585/&(83*8(</>#$(%J(@3#&(*(J+/'+*>(5$(+%&&5&'1

bc<#J85/&(!*&?05&'(Q(F&(*JJ+/*<3(83*8($#J*+*8#$(*(J+/'+*>m$(&/+>*0(</?#(G+/>(58m$(#++/+Q3*&?05&'(</?#1

;3+/@(Q(;/(83+/@(*&(#c<#J85/&(5$(8/(<+#*8#(*&(#c<#J85/&(/AD#<8(*&?(J*$$(58(/GG(8/(83#(+%&Q85>#(#&H5+/&>#&81(;35$(5$

?/&#(#cJ05<58"(5&(</?#(%$5&'(83#(throw(,#"@/+?1

.8*<,(;+*<#QF($8*<,(8+*<#(5$($/>#85>#$(<*00#?(*($8*<,(A*<,8+*<#(/+(#H#&(D%$8(*(A*<,8+*<#1(;3#($8*<,(8+*<#5$(*(05$8(/G

$8*<,(G+*>#$1(F($8*<,(G+*>#(5&?5<*8#$(*(>/>#&8(?%+5&'(*&(*JJ05<*85/&m$(#c#<%85/&(@3#&(*(>#83/?(5$(<*00#?1(F($8*<,

G+*>#(</&8*5&$(5&G/+>*85/&(*A/%8(@3#+#(83#(>#83/?(@*$(<*00#?(G+/>(5&(83#(6*H*($/%+<#(</?#1(./(83#(6*H*($8*<,

8+*<#('#&#+*8#?(@3#&(*&(#c<#J85/&(5$(<*00#?(5$(*(05$8(/G(G+*>#$(83*8($8*+8$(*8(05&#(5&(83#(>#83/?(83#(#c<#J85/&

/<<%++#?(*&?(#c8#&?$(A*<,(8/(@3#&(83#(J+/'+*>($8*+8#?1

4.12. Exercises

4.12.1. Exercise 1

7+#*8#(*($5>J0#(*??585/&(<*0<%0*8/+(5&(6*H*1(;3#(J+/'+*>($3/%0?(J+/>J8(83#(%$#+(8/(#&8#+(E(5&8#'#+$-(83#&(*??$(83#

&%>A#+$(*&?(J+5&8$(83#(+#$%081(S*,#($%+#(83#(J+/'+*>(5&<0%?#$(*JJ+/J+5*8#(#c<#J85/&(3*&?05&'(5&(<*$#(83#(%$#+

?/#$(&/8(#&8#+(*JJ+/J+5*8#(5&8#'#+(H*0%#$1

4.12.2. Exercise 2

4+58#(*(6*H*(J+/'+*>(8/(+*&?/>0"(<+#*8#(*&(*++*"(/G(LT(?/%A0#(H*0%#$1()+/>J8(83#(%$#+(8/(#&8#+(*&(5&?#c(*&?

J+5&8$(83#(</++#$J/&?5&'(*++*"(H*0%#1(=&<0%?#(#c<#J85/&(3*&?05&'(83*8(J+#H#&8$(83#(J+/'+*>(G+/>(8#+>5&*85&'(5G

*&(/%8(/G(+*&'#(5&?#c(5$(#&8#+#?(A"(83#(%$#+1(O!=j;B(;3#(#c<#J85/&(83+/@&(@500(A#(F++*"=&?#cU%8UG`/%&?$R

4.12.3. Exercise 3

4/5/21, 10)50 PMIntermediate Programming

Page 85 of 185http://itec2150.gitlab.io/

7+#*8#(*(<%$8/>(bc<#J85/&(&*>#?(IllegalTriangleSideException1(7+#*8#(*(<0*$$(&*>#?(;+5*&'0#1(;3#(;+5*&'0#

<0*$$($3/%0?(</&8*5&(I(?/%A0#(H*+5*A0#$(</&8*5&5&'(83#(0#&'83(/G(#*<3(/G(83#(8+5*&'0#$(83+##($5?#$1(7+#*8#(*

</&$8+%<8/+(@583(83+##(J*+*>#8#+$(8/(5&585*05a#(83#(83+##($5?#$(/G(83#(8+5*&'0#1(F??(*&(*??585/&*0(>#83/?(&*>#?

<3#<,.5?#$(@583(>#83/?(3#*?#+(Q(sA//0#*&(<3#<,.5?#$OR(83+/@$(=00#'*0;+5*&'0#.5?#bc<#J85/&(s1(4+58#(</?#($/(83*8

<3#<,.5?#$(>*,#$($%+#(83*8(83#(83+##($5?#$(/G(83#(8+5*&'0#(>##8(83#(J+/J#+(<+58#+5*(G/+(*(8+5*&'0#1(=8(@500(+#8%+&(8+%#

5G(*&?(/&0"(5G(83#($%>(/G($5?#Cv($5?#E(5$('+#*8#+(83*&($5?#I(Fj2(83#($%>($5?#Ev$5?#I(5$('+#*8#+(83*&($5?#C(Fj2(83#

$%>(/G($5?#Cv($5?#I(5$('+#*8#+(83*&($5?#E1(=G(*&"(/G(83/$#(83+##(</&?585/&$(5$(&/8(>#8-(83#(>#83/?(@500(<+#*8#(*&?

83+/@(*&(=00#'*0;+5*&'0#.5?#bc<#J85/&1(F??(*(>*5&(>#83/?(8/(<+#*8#(*&?(<3#<,(8@/(8/(83+##(?5GG#+#&8(8+5*&'0#$1

4.13. Issue Tracker/Comments

=$$%#(;+*<,#+ O388J$BPP'583%A1</>P3J*+,WP3#0JY?#$,P5$$%#$R

4/5/21, 10)50 PMIntermediate Programming

Page 86 of 185http://itec2150.gitlab.io/

5. File Input/Output

5.1. Learning Outcomes

2#$<+5A#(83#(?5GG#+#&<#(A#8@##&(8#c8(*&?(A5&*+"(G50#$

F<<#$$(O/J#&R(G50#$(G/+(+#*?5&'(*&?(@+585&'

N#*+&(83#(</>>/&(G50#(3*&?05&'(#c<#J85/&$(*&?(3/@(8/(3*&?0#(83#>

Z$#(83#(F)=(<0*$$#$(`%GG#+#?V50#l#*?#+(*&?(`%GG#+#?V50#4+58#+(G/+(8#c8(G50#(*<<#$$

Z$#(.<*&&#+(8/(+#*?(*&?(J*+$#(8#c8(G50#$1

Z&?#+$8*&?(83#(J%+J/$#(/G(*&?(%$#(+#'%0*+(#cJ+#$$5/&$

Z$#()+5&84+58#+(8/(/%8J%8(8/(*&?(<+#*8#(8#c8(G50#$1

5.2. Resources

5.2.1. Text and Tutorials

=&8+/?%<85/&(8/()+/'+*>>5&'(Z$5&'(6*H*Q(b5'383(b?585/&(A"(2*H5?(61(b<,B

388JBPP>*8313@$1#?%PD*H*&/8#$P<CCP5&?#c138>0(73*J8#+(CC(Q(=&J%8PU%8J%8(.8+#*>$-(V50#$(*&?(j#8@/+,5&'

6*H*-(6*H*-(6*H*B(UAD#<8QU+5#&8#?()+/A0#>(./0H5&'(AA"(l*0J3(S/+#005(*&?(l*0J3(4*0?#B

388JBPP@@@1<$18+5&</001#?%Pt+*>PDDDPDDDQ/$QETCWTMEL1J?G(73*J8#+(K(*&?(73*J8#+(CC(V50#$(*&?(.8+#*>$

6*H*(F)=(D*H*15/(J*<,*'#(+#G#+#&<#(B

388J$BPP?/<$1/+*<0#1</>P#&PD*H*PD*H*$#PCCP?/<$P*J5PD*H*1A*$#PD*H*P5/PJ*<,*'#Q$%>>*+"138>0

U+*<0#(6*H*(;%8/+5*0(/&(l#'%0*+(bcJ+#$$5/&$B(388J$BPP?/<$1/+*<0#1</>PD*H*$#P8%8/+5*0P#$$#&85*0P+#'#cP5&?#c138>0

5.2.2. Videos

h5?#/(/&(3/@(8/(+#*?(G50#$(%$5&'(.<*&&#+(B(388J$BPP@@@1"/%8%A#1</>P@*8<3\H]Ilj9Z_cF'>@

h5?#/(/&(3/@(8/(@+58#(G50#$(@583()+5&84+58#+(B(388J$BPP@@@1"/%8%A#1</>P@*8<3\

H]`@$^*p%F<?'k05$8])NVbE7bT^2[IbbIbE[k5&?#c][Ck8]T

h5?#/(/&(+#*?5&'(*&?(@+585&'(G50#Q(/&0"(G5+$8(8#&(>5&%8#$(5$(/&(8#c8(G50#$(B(388J$BPP@@@1"/%8%A#1</>P@*8<3\

H]YD37H"[Y0qb

5.3. Overview

7/>J%8#+(G50#$(*+#(%$#?(8/($8/+#(</00#<85/&$(/G(?*8*(/&(*(</>J%8#+($8/+*'#(?#H5<#($%<3(*$(*(3*+?(?+5H#1(6*H*

</&8*5&$(*($#+5#$(/G(F)=(<0*$$#$(8/(*5?(5&(83#(+#*?5&'(*&?(@+585&'(/G(?*8*(8/(*&?(G+/>(83#$#(G50#$1(=&(835$(<3*J8#+-(@#

?5$<%$$(8#c8(G50#(5&J%8(*&?(/%8J%81(;#c8(G50#$(<*&(A#(H5#@#?(*$(</>J%8#+(G50#$(</&8*5&5&'(*(</00#<85/&(/G(Z&5</?#(O/+

*($%A$#8(/G(Z&5</?#($%<3(*$(F.7==R(<3*+*<8#+$1(;"J5<*00"-(83#(?*8*(5$(/+'*&5a#?(5&8/(*($#+5#$(/G($8+5&'$(@35<3(<*&(A#

+#*?(5&8/(*(</>J%8#+(J+/'+*>1(`5&*+"(G50#$(*+#(*(</00#<85/&(/G(A5&*+"(</?#?(?*8*(5&(83#(&*85H#(G/+>*8(/G(83#

</>J%8#+(*&?(+#d%5+#$(*(?5GG#+#&8($#8(/G(F)=(<0*$$#$(8/(J+/<#$$(83#(?*8*1(;#c8(G50#$(*+#(%$#G%0(8/(J+/'+*>>#+$(*$

83#"(<*&(A#(%$#?(8/($8/+#(3%>*&(+#*?*A0#(?*8*(83*8(<*&(A#(#?58#?(#583#+(@5835&(*(6*H*(J+/'+*>(/+(#c8#+&*00"(%$5&'

4/5/21, 10)50 PMIntermediate Programming

Page 87 of 185http://itec2150.gitlab.io/

8#c8(#?58/+$1(b*<3(G50#(3*$(*($3/+8(&*>#(@583(*(G50#(#c8#&$5/&($%<3(*$(r!4C1D*H*r(*&?(*(J*83(&*>#1(;3#(J*83(&*>#

?#$<+5A#$(@3#+#(83#(G50#(5$($8/+#?(/&(83#(</>J%8#+($8/+*'#(?#H5<#1(=&($/>#(</>J%8#+$(835$(5$(,&/@&(*$(83#

?5+#<8/+"(/+(G/0?#+(0/<*85/&1(=&(*(45&?/@$(3*+?(?+5H#-(*&(#c*>J0#(/G(*(J*83(&*>#(>5'38(A#B

r7BwwZ$#+$ww<D/3&$ELww4/+,$J*<#ww!/>#@/+,Cww$+<r(1(j/8#(83*8(@3#&(%$5&'(83#(w(<3*+*<8#+(5&$5?#(*(6*H*(.8+5&'(8"J#-

@#(+#J#*8(58(8@5<#(A#<*%$#(83*8(<3*+*<8#+(5$(%$#?(8/(5&?5<*8#(*($J#<5*0(&/&J+5&85&'(<3*+*<8#+(5&$5?#(83#(.8+5&'1(;35$

<3*J8#+(#cJ0/+#$(3/@(8/(+#*?(*&?(%$#(?*8*(G+/>(*(8#c8(G50#(5&(*(6*H*(J+/'+*>(5&(*(</%J0#(/G(?5GG#+#&8(@*"$1(=8(*0$/

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<0*$$#$(5&(83#(D*H*15/(J*<,*'#1

5.4. Streams and Files

F00(?*8*(G+/>(#c8#+&*0($/%+<#$(</>5&'(5&8/(/+(/%8(/G(*(6*H*(J+/'+*>(%$#$($8+#*>$1(.8+#*>$(*+#(/&#(@*"

</&&#<85/&$(A#8@##&(*&(#c8#+&*0(?*8*($/%+<#(*&?(83#(6*H*(J+/'+*>1(=8(5$(%$#G%0(8/(835&,(/G(83#>(*$(*(J5J#(@3#+#

/&0"(/&#(J5#<#(/G(?*8*(>*"(G0/@(*8(*(85>#1(2*8*(<*&(*0$/(/&0"(G0/@(/&#(@*"1(./(@#(%$#(?5GG#+#&8($8+#*>$(G/+(+#*?5&'

*(G50#(*&?(@+585&'(*(G50#1(9/%(3*H#(A##&(%$5&'(83#(System.in($8+#*>(G/+(+#*?5&'(?*8*(G+/>(83#(</>J%8#+(,#"A/*+?1

9/%(3*H#(*0$/(A##&(@+585&'(?*8*(%$5&'(83#(System.out($8+#*>(8/(@+58#(8/(83#(</&$/0#(G/+(83#(%$#+(8/($##1(;3#

$8+#*>$(%$#?(8/(+#*?(*&?(@+58#(G50#$(/J#+*8#($5>50*+0"(*&?("/%(@500(+#</'&5a#($/>#(/G(83#(>#83/?$(@#(@500(%$#(8/

+#*?(*&?(@+58#(8/(G50#$1

5.5. The File class

`#G/+#(@#(<*&(+#*?(/+(@+58#(*(G50#-(@#(>%$8(r/J#&r(83#(G50#(G/+(+#*?5&'(*&?(@+585&'1(;3#(+%&Q85>#($"$8#>(3*$(A##&

8*,5&'(<*+#(/G(/J#&5&'(83#($8+#*>$(G/+(%$#+(5&J%8(*&?(/%8J%8-(A%8(83#(J+/'+*>>#+(5$(+#$J/&$5A0#(G/+(/J#&5&'(83#

$8+#*>$(G/+(G50#(3*&?05&'1(;3#(G5+$8($8#J(5$(8/(<+#*8#(*&(5&$8*&<#(/G(83#(V50#(<0*$$(@35<3(</&8*5&$(*00(83#(5&G/+>*85/&

83#($"$8#>(&##?$(8/(,&/@(*A/%8(83#(0/<*85/&(/G(83#(G50#1(=8(J+/H5?#$(*(J0*8G/+>(5&?#J#&?#&8(+#J+#$#&8*85/&(/G(83#

G50#$(&*>#(*&?(?5+#<8/+"(5&G/+>*85/&1(9/%(<*&(<+#*8#(*(V50#(5&$8*&<#(%$5&'(/&0"(83#(&*>#(/G(83#(G50#(*&?(*00/@(83#

=2b(8/(0//,(G/+(58(5&(83#(?#G*%08(?5+#<8/+"(G/+(G50#(5&J%81(!/@#H#+-(835$(?#G*%08(?5+#<8/+"(5$(?5GG#+#&8(G/+(?5GG#+#&8

=2bm$1(7/&$%08("/%+(=2b(?/<%>#&8*85/&(G/+(83#(?#G*%08(G50#(?5+#<8/+"(5G("/%(?#$5+#(8/(%$#(/&0"(83#(G50#(&*>#1

!/@#H#+-(58(5$(A#$8(8/(%$#(*(G%00"(+#*05a#?(J*83(&*>#(@3#&(<+#*85&'(83#(G50#1(;35$(5$('/5&'(8/(A#(?5GG#+#&8(?#J#&?5&'

%J/&(83#(/J#+*85&'($"$8#>(/G(83#(</>J%8#+("/%(*+#(%$5&'1(l#G#+(8/("/%+(/J#+*85&'($"$8#>(+#G#+#&<#(8/(G5'%+#(/%8

G%00"(+#*05a#?(J*83(&*>#$1

// creating a File instance using the default directory

importimport java.io.Filejava.io.File;

File myFile = newnew File("Hw1.txt");

JAVA

// creating a file using fully realized path name in Windows

import java.io.File;

// remember to get a single \ in a Java string we have to put \\

File myFile = new File("C:\\Users\\cjohns25\\Desktop\\HW1.txt");

// a full realized path name on an Apple MacBook

File myMacFile = new File("/users/cjohns25/Documents/2150/HW1.txt");

4/5/21, 10)50 PMIntermediate Programming

Page 88 of 185http://itec2150.gitlab.io/

U&<#(@#(3*H#(<+#*8#?(*(V50#(/AD#<8(G/+(83#(G50#(@#(@5$3(8/(5&8#+*<8(@583-(@#(*+#(+#*?"(8/(/J#&(/%+(?*8*($8+#*>(8/

83#(G50#1

5.6. BuﬀeredReader and BuﬀeredWriter

;3#+#(*+#(*<8%*00"($#H#+*0(@*"$(8/(+#*?(*&?(@+58#(G+/>(8#c8(G50#$(%$5&'(83#(6*H*(F)=(<0*$$#$1(4#(*+#('/5&'(8/(0//,(*8

$/>#(</>>/&(@*"$(8/(?/($/1(;#c8(G50#$(8"J5<*00"(</&$5$8(/G(3%>*&(+#*?*A0#(<3*+*<8#+$1(43#&(?#*05&'(@583(05&#$(/G

8#c8-(83#(#*$5#$8(<0*$$(8/(%$#(G/+(+#*?5&'(83/$#(05&#$(/G(8#c8(5&(5$(83#(BufferedReader(<0*$$1(;3#(*$$/<5*8#?(/%8J%8

<0*$$(G/+(@+585&'(8/(G50#$(5$(,&/@&(*$(BufferedWriter1(;3#+#(*+#(05>58*85/&$(@583(83#$#(<0*$$#$($5&<#(83#"(<*&(/&0"

+#*?(/+(@+58#(05&#$(/G(8#c81(BufferedReader(3*$(*(>#83/?(&*>#?(+#*?N5&#OR(G/+(+#*?5&'(*(05&#(/G(8#c81(;3#

#c*>J0#(A#0/@($3/@$(*&(#c*>J0#(/G(+#*?5&'(05&#$(/G(8#c8(G+/>(*(G50#(&*>#?(r8#c818c8r(*&?(83#&(@+585&'(8/(83#

</&$/0#(%$5&'(System.out1

;3#(BufferedReader(*&?(BufferedWriter(<0*$$(*+#(%$#G%0(@3#&(?#*05&'(@583(0*+'#(<3%&,$(/G(?*8*1(;35$(5$(%$#G%0

5&(<#+8*5&($58%*85/&$(@3#&(?#*05&'(@583(#c8#+&*0(?#H5<#$(83*8(?#*0(5&(0*+'#(<3%&,$(/G(?*8*-(A%8(&/8($/(>%<3(@3#&

8+"5&'(8/(8*,#(?5$<+#8#(J5#<#$(/G(?*8*(G+/>(*(G50#(*&?(J0*<#(83#>(5&8/(H*+5/%$(H*+5*A0#$1(N#8m$(0//,(*8(*&(#c*>J0#

@3#+#(835$(>5'38(A#(%$#G%01

5.6.1. An Example using BuﬀeredReader and BuﬀeredWriter

;3#(G/00/@5&'(#c*>J0#($3/@$(3/@(8/(%$#(`%GG#+#?l#*?#+(*&?(`%GG#+#?4+58#+(8/(</J"(G+/>(/&#(G50#(8/(*&/83#+1(=&

835$(</?#-(*(G50#(&*>#?(r#c*>J0#18c8r(5$(</J5#?(<3*+*<8#+(A"(<3*+*<8#+(5&8/(*(&#@(G50#(8580#?(r#c*>J0#7/J"18c8r1(j/8#

83*8(5G(83#(8#c8(G50#(r#c*>J0#7/J"18c8r(*0+#*?"(#c5$8$-(835$(J+/'+*>(@500(#+*$#(*&"(</&8#&8(<%++#&80"(5&(83#(G50#1

importimport java.io.Filejava.io.File;

importimport java.io.BufferedReaderjava.io.BufferedReader;

...

File f = newnew File("text.txt");

BufferedReader buffer = nullnull;

trytry

{

buffer= newnew BufferedReader(newnew FileReader(f));

String aLine = buffer.readLine();

System.out.println(aLine);

}

catchcatch (IOException ex)

{

// code to handle either an empty file or nonexistent file

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 89 of 185http://itec2150.gitlab.io/

5.7. PrintWriter

;3#(>/$8(</>>/&(@*"(8/(@+58#(8/(*(8#c8(G50#(5$(83+/%'3(83#(%$#(/G(83#(java.io.PrintWriter(<0*$$1(=8(5$(<*J*A0#(/G

@+585&'(*(H*+5#8"(/G(?*8*(8"J#$(*&?(5$(d%58#(H#+$*850#1(9/%(3*H#(*0$/(A##&(%$5&'(83#()+5&84+58#+(>#83/?$(#H#+"85>#

"/%(@+58#(8/(83#(</&$/0#1(System.out(5$(*&(/AD#<8(/G(8"J#()+5&84+58#+1(Z&05,#(."$8#>1/%8-(58(5$(&#<#$$*+"(8/(/J#&(*

/**

* This example shows how to copy one text file to another using BufferedReader

* BufferedWriter classes. Requires that the file "example.txt" be in the

* default file directory for your IDE.

importimport java.io.Filejava.io.File;

importimport java.io.FileReaderjava.io.FileReader;

importimport java.io.FileWriterjava.io.FileWriter;

importimport java.io.IOExceptionjava.io.IOException;

importimport java.io.BufferedReaderjava.io.BufferedReader;

importimport java.io.BufferedWriterjava.io.BufferedWriter;

publicpublic classclass BufferedWriterExample

{

publicpublic staticstatic voidvoid main(String[] args)

{

File readFile = newnew File("example.txt");

File writeFile = newnew File("exampleCopy.txt");

BufferedReader readBuffer = nullnull;

BufferedWriter writeBuffer = nullnull;

// open files for reading and writing

intint readResult = 0;

trytry

{

readBuffer = newnew BufferedReader(newnew FileReader(readFile));

writeBuffer = newnew BufferedWriter(newnew FileWriter(writeFile));

dodo

{

readResult = readBuffer.read();

// -1 = nothing to read

ifif (readResult != -1)

{

writeBuffer.write((charchar) readResult);

}

} whilewhile (readResult != -1);

writeBuffer.close();

readBuffer.close();

} catchcatch (IOException ex)

{

ex.printStackTrace();

System.out.println("Problem with files");

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 90 of 185http://itec2150.gitlab.io/

G50#(*&?(<+#*8#(*&(/AD#<8(/G(8"J#()+5&8@+58#+(*$$/<5*8#?(@583(#*<3(G50#("/%(*+#(@+585&'1(;3#(</&$8+%<8/+$(G/+

)+5&84+58#+(*00/@("/%(8/(<+#*8#(@583(#583#+(*(V50#(/AD#<8(/+(D%$8(*(.8+5&'(</&8*5&5&'(83#(G50#(&*>#1(bc*>J0#$(A#0/@

$3/@(A/83(@*"$(/G(/J#&5&'(*(8#c8(G50#(G/+(@+585&'1

`/83(@*"$(/G(/J#&5&'(83#(G50#(*+#(#d%*00"(#GG#<85H#(*&?(#GG5<5#&81(S/$8(J+/'+*>>#+$(<3//$#(83#($#</&?(@*"

A#<*%$#(58(+#d%5+#$(0#$$(J+/'+*>>5&'1(=&(83#(#c*>J0#($3/@&-(*($5>J0#(.8+5&'(058#+*0(@*$(@+588#&(8/(83#(G50#(%$5&'

83#(println()(>#83/?1(9/%(3*H#(A##&(%$5&'(println(*&?(print(>#83/?$(8/(@+58#(8/(83#(</&$/0#1(4+585&'(8/(*(G50#

%$5&'(83#>(5&(*&(5?#&85<*0(G*$35/&1

j/8#B(UJ#&5&'(*&?(@+585&'(8/(*(G50#(3*$(J/8#&85*0(8/('#&#+*8#(/&#(/G($#H#+*0(<3#<,#?(#c<#J85/&(83*8(5&3#+58(G+/>

IOException1(;3#+#G/+#-(58(5$(5>J/+8*&8(8/(/J#&(*&?(J+/<#$$(G50#$(%$5&'(J+/J#+(#c<#J85/&(3*&?05&'1

5.7.1. Example of writing data to a text ﬁle

=&(835$(#c*>J0#-(83#(%$#+(5$(J+/>J8#?(G/+(*(G50#(&*>#1(F(8#c8(G50#(/G(83*8(&*>#(5$(<+#*8#?(*&?(@+588#&(8/1(=8(5$

5>J/+8*&8(8/(&/8#(83*8(5G(83#(&*>#?(G50#(*0+#*?"(#c5$8$(5&(83#(G50#(J*83(%$#?-(58(@500(#+*$#(83#(<%++#&8(</&8#&8$(/G(83*8

G50#(*&?(+#J0*<#(83#>(@583(83#(8#c8(5&(83#(#c*>J0#1(F0$/-(835$(5$(83#(G5+$8(85>#("/%(3*H#($##&(83#(%$#(/G(83#(finally

A0/<,(5&(83#(8+"P<*8<3(A0/<,$(%$#?(G/+(#c<#J85/&(3*&?05&'1(;3#(</?#(5&(83#(<%+0"(A+*<#$(/G(83#(finally(A0/<,(5$

#c#<%8#?(+#'*+?0#$$(/G(@3#83#+(83#(</?#(5&(83#(8+"(A0/<,(#c#<%8#$(@583/%8(J+/A0#>(/+(*&(#c<#J85/&(5$

File f = newnew File("outText.txt");

PrintWriter myWriter = nullnull;

trytry

{

// open the file using a File object

myWriter = newnew PrintWriter(f);

myWriter.println("I am writing this to the file");

myWriter.close();

}

catchcatch (IOException ex)

{

// handle exception generated if system can not open or write to file

}

JAVA

//same example- opening file using only file name

PrintWriter myWriter = nullnull;

trytry

{

// open the file using a File object

myWriter = newnew PrintWriter("outText.txt");

myWriter.println("I am writing this to the file");

myWriter.close();

}

catchcatch (IOException ex)

{

// handle exception generated if system can not open or write to file

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 91 of 185http://itec2150.gitlab.io/

#&</%&8#+#?1(;3#(%$#(5&(835$(#c*>J0#(5$(</>>/&(*$(@#(*+#(<0/$5&'(83#(G50#(5&(83#(G5&*00"(A0/<,1(F(G50#(A#5&'(@+588#&

8/(@35<3(5$(&/8(<0/$#?(J+/J#+0"(*8(83#(#&?(/G(83#(J+/'+*>(5$(&/8('%*+*&8##?(8/(</&8*5&(83#(8#c8(@+588#&(A"(83#

J+/'+*>1(70/$5&'(/G(83#(G50#$(5&(*(finally(A0/<,(5$(*(</>>/&(%$#(/G(83#(A0/<,(*&?(5$(</&$5?#+#?(*(A#$8(J+*<85<#(G/+

J+/'+*>>#+$1(;3#(</>J50#+(@500(@*+&("/%(5G(83#(G50#(5$(&/8(<0/$#?-(A%8(@500(*00/@("/%(8/(+%&("/%+(J+/'+*>(@583/%8

J+/J#+0"(<0/$5&'(83#(G50#1

importimport java.io.Filejava.io.File;

importimport java.io.IOExceptionjava.io.IOException;

importimport java.io.PrintWriterjava.io.PrintWriter;

importimport java.util.Scannerjava.util.Scanner;

/**

* Example of opening a text file for writing and writing various information to

* it.

publicpublic classclass WriteTextFile

{

publicpublic staticstatic voidvoid main(String[] args)

{

// declare variables before try/catch block to avoid scope issues

// scanner to allow user input values

Scanner consoleInput = newnew Scanner(System.in);

// variable for file name

String fileName;

// variable to hold info about the File

File theFile;

// PrintWriter object to open for writing to file

PrintWriter outputFile = nullnull;

// open file with proper exception handling

booleanboolean fileOpen = falsefalse;

whilewhile (!fileOpen)

{

trytry

{

// ask user for a file name

System.out.println("Please enter name of file to be created and written to:");

fileName = consoleInput.nextLine();

theFile = newnew File(fileName);

outputFile = newnew PrintWriter(theFile);

fileOpen = truetrue;

} catchcatch (IOException ex)

{

System.out.println("Unable to open that file- check directory information and file name");

}

// using a second try/catch block to separate writing errors from

// file opening errors

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 92 of 185http://itec2150.gitlab.io/

5.8. Scanner

;3#(<0*$$(@#(%$#(8/(+#*?(5&?5H5?%*0(A58$(/G(?*8*(G+/>(*(8#c8(G50#(5$(Scanner1(9#$(835$(5$(83#($*>#(.<*&&#+(<0*$$(@#

%$#(G/+(+#*?5&'(5&J%8(G+/>(83#(,#"A/*+?1(./("/%(*+#(*0+#*?"(G*>505*+(@583(83#(</>>/&(>#83/?$(G/+(+#*?5&'

5&G/+>*85/&1(s&#c8OR(Q(G/+(+#*?5&'(*(.8+5&'(s&#c8N5&#OR(Q(G/+(+#*?5&'(*(05&#(/G(8#c8(8#+>5&*8#?(A"(83#(#&?(/G(05&#

<3*+*<8#+(s&#c8=&8OR(Q(G/+(+#*?5&'(*&(5&8#'#+(s&#c82/%A0#OR(Q(G/+(+#*?5&'(*(?/%A0#

43#&(+#*?5&'(G+/>(83#(,#"A/*+?-(@#(<+#*8#(*(.<*&&#+(/AD#<8(*&?(J*$$(83#(System.in(/AD#<8(*$(*(J*+*>#8#+(*8

</&$8+%<85/&1(;/(%$#(.<*&&#+(8/(+#*?(G+/>(*(V50#-(@#(<+#*8#(83#(.<*&&#+(/AD#<8(A"(J*$$5&'(#583#+(*(V50#(/AD#<8(/+

.8+5&'(</&8*5&5&'(83#(G50#(&*>#($5>50*+(8/()+5&84+58#+1(F0$/-(%&05,#(+#*?5&'(G+/>(83#(,#"A/*+?-(<+#*85&'(*(.<*&&#+

/AD#<8(05&,#?(8/(*(G50#(<*&(J/8#&85*00"('#&#+*8#(*(<3#<,#?(#c<#J85/&($/(58(5$(5>J/+8*&8(8/(%$#(J+/J#+(#c<#J85/&

3*&?05&'1(.##(83#(8@/(#c*>J0#$(G/+(/J#&5&'(*(.<*&&#+(8/(+#*?(*(G50#($3/@&(A#0/@1

trytry

{

// file opened for writing - let's put something in there

outputFile.println("This is how to write a string literal to a file");

doubledouble x = 55.6;

outputFile.println("This is how to print a double value: " + x);

intint y = 10;

String s = "This is a string variable";

outputFile.println(s + " this is an integer " + y);

} catchcatch (Exception ex)

{

// print the stack trace so programmer can see what line the exception

// occurred on

ex.printStackTrace();

// tell the user something

System.out.println("Unable to write to the file- program is terminating");

} finallyfinally

{

// regardless of whether exception occurred- close the file opened for writing

outputFile.close();

}

4/5/21, 10)50 PMIntermediate Programming

Page 93 of 185http://itec2150.gitlab.io/

j/8#(*A/H#(83*8(@#(%$#?(*(&#@(>#83/?(/&(.<*&&#+(83*8(@#(?5?&m8(%$#(@583(83#(,#"A/*+?1(;35$(>#83/?(5$(3*$j#c8OR1

;35$(>#83/?(5&?5<*8#$(@3#83#+(/+(&/8(83#+#(5$(*&"(+#>*5&5&'(?*8*(5&(83#(G50#(83*8(3*$(&/8(*0+#*?"(A##&(+#*?1(=8(?/#$

&/8(+#*?(83#(?*8*Q(58($5>J0"(5&?5<*8#$(83*8(83#+#(5$($8500(?*8*("#8(8/(A#(+#*?1(l#>#>A#+-(@#(*+#(+#*?5&'(G+/>(*

$8+#*>(/G(?*8*(*&?(<*&(/&0"(+#*?(#*<3(J5#<#(/G(?*8*(/&<#1(=8(5$(*0$/(&/8(J/$$5A0#(8/(+#+#*?(?*8*($/(A#(H#+"(<*+#G%0

&/8(8/(83+/@(?*8*(*@*"1

5.8.1. How does Scanner work?

;3#(>#83/?$(5&(.<*&&#+(%$#?(8/(+#*?(?*8*-(+#*?(5&J%8($#J*+*8#?(A"(?#05>58#+$1(2#05>58#+$(*+#(83#(&/&J+5&85&'

<3*+*<8#+$(%$#?(8/(G/+>*8(83#(8#c8($%<3(*$(A0*&,($J*<#$-(8*A$(*&?(#&?(/G(05&#(<3*+*<8#+$1(;3#(>#83/?$(*A/H#(G5+$8

$,5J(*(?#05>58#+(*&?(83#&(+#*?(<3*+*<8#+$(%&850(*&/83#+(?#05>58#+(5$(#&</%&8#+#?1(;3#"(?/(&/8(+#*?(83#($#</&?

?#05>58#+1(;3#(<3*+*<8#+$(+#*?(*+#(83#&(</&H#+8#?(8/(83#(?#$5+#?(8"J#(5&?5<*8#?(A"(@35<3(>#83/?(@*$(<*00#?1(=G(83#

<3*+*<8#+$(?/(&/8(>*8<3(@3*8(@*$(*$,#?(G/+-(*&(=&J%8S5$>*8<3bc<#J85/&(5$('#&#+*8#?1(V/+(#c*>J0#-(5G(83#(>#83/?

nextInt()(5$(<*00#?(*&?(83#(<3*+*<8#+$(+#*?(</&8*5&(*(&/&Q&%>#+5<(<3*+*<8#+-(*&(#c<#J85/&(@500(A#('#&#+*8#?1(;3#

>#83/?$(next()(*&?(nextLine()(+#*?(*&?(</&H#+8(<3*+*<8#+$(8/(.8+5&'$1(;3#(nextLine()(>#83/?(/&0"(%$#$(#&?(/G

05&#(<3*+*<8#+$(*$(?#05>58#+$1(;3#(#&?(/G(05&#(<3*+*<8#+(5$(<*00#?(*(05&#($#J*+*8/+(5&(6*H*(*&?(5$(?#G5&#?(5&(*(.8+5&'

*$(w+(/+(w&(5&(45&?/@$(*&?(w&(/&(Z&5c1(=8(5$(J0*8G/+>(?#J#&?#&8Q(*$(*(+#$%08("/%(>*"(/<<*$5/&*00"($##(5$$%#$(%$5&'

nextLine()(/&(<+/$$(J0*8G/+>(G50#$1

V50#$(<*&(*0$/(A#(+#*?(*<+/$$(83#(5&8#+&#8(*$$%>5&'(83#(G50#(?#$5+#?(8/(A#(+#*?(3*$(*(ZlN1(=&$8#*?(/G(<+#*85&'(*(V50#

/AD#<8(8/(%$#(5&(</&$8+%<85&'(.<*&&#+-(*(D*H*1&#81ZlN(/AD#<8(5$(<+#*8#?1

5.8.2. File reading Examples

File f = newnew File("dataFile.txt);

Scanner fileScanner = null;

try

{

fileScanner = new Scanner(f);

alternately could have written

fileScanner = new Scanner("dataFile.txt");

whilewhile (!fileScanner.hasNext())

{

// read the next piece of data in the file- this example shows all String data

String data = fileScanner.next();

}

fileScanner.close();

}

catchcatch (IOException ex)

{

// code to handle a problem opening or reading from the file.

}

JAVA

// opening a file using a URL

String URLString = "www.somedomain.com/someFile.txt";

java.net.URL theURL = newnew java.net.URL(URLString);

Scanner urlReader = newnew Scanner(theURL);

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 94 of 185http://itec2150.gitlab.io/

;3#+#(*+#(0/8$(/G(@*"$(8/(+#*?(?*8*(G+/>(*(8#c8(G50#1(F&?(58(>/$80"(?#J#&?$(/&(83#(G/+>*8(/G(83#(8#c8(G50#1(./(A#G/+#

@+585&'(83#(J+/'+*>(8/(+#*?(*(G50#-(83#(J+/'+*>>#+($3/%0?(A#(*@*+#(/G(83#(G/+>*8(/G(83#(?*8*1(=&(835$(G5+$8

#c*>J0#-(83#(G50#(&*>#(5$(?#8#+>5&#?(A"(J+/>J85&'(83#(%$#+(8/(#&8#+(581(;3#&(#*<3(05&#(/G(83#(8#c8(G50#(5$(+#*?(*$(*

.8+5&'1(`"(+#*?5&'(83#(?*8*(*$(*(.8+5&'-(83#(J+/'+*>>#+(?/#$(&/8(3*H#(8/(,&/@(5G(83#(<3*+*<8#+$(+#*?(*+#(8#c8-

&%>#+5<(/+($">A/05<1(!/@#H#+-(/&<#(+#*?(83*8(@*"-(58(>%$8(A#(J*+$#?(8/(%$#(*$(*&"835&'(/83#+(83*&(*(.8+5&'1

importimport java.io.Filejava.io.File;

importimport java.io.FileNotFoundExceptionjava.io.FileNotFoundException;

importimport java.io.IOExceptionjava.io.IOException;

importimport java.io.PrintWriterjava.io.PrintWriter;

importimport java.util.Scannerjava.util.Scanner;

/**

* This example shows how to open a text file for reading and read each line as

* a String and print to console

publicpublic classclass ReadStringsFromFile

{

publicpublic staticstatic voidvoid main(String[] args)

{

// declare variables before using in try/catch loop to avoid scope issues

// open a Scanner for user input

Scanner consoleInput = newnew Scanner(System.in);

String fileName = nullnull;

File theFile = nullnull;

Scanner inputFile = nullnull;

// open file with proper exception handling

booleanboolean fileOpen = falsefalse;

whilewhile (!fileOpen)

{

trytry

{

// ask user for a file name

System.out.println("Please enter name of file to be created and written to:");

fileName = consoleInput.nextLine();

theFile = newnew File(fileName);

inputFile = newnew Scanner(theFile);

fileOpen = truetrue;

} catchcatch (FileNotFoundException ex)

{

System.out.println("Unable to open that file- check to make sure directory is corerct and file

exists");

}

// now read from the file - note- program will loop until valid file name

// entered

trytry

{

// continue to read while file contains info

whilewhile (inputFile.hasNextLine())

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.%JJ/$#(@#(@*&8(8/(+#*?(*(A%&<3(/G(&%>A#+$(G+/>(G50#1(V/+(#c*>J0#-(@#(>5'38(3*H#(*(G50#(&*>#?(&%>A#+$18c8

83*8(</&8*5&$(*(A%&<3(/G(8#$8('+*?#$(83*8(@#(@*&8(8/(*H#+*'#1(;3#(8#c8(G50#(>5'38(0//,(05,#(835$B

=G(@#(%$#(83#(G5+$8(#c*>J0#-(83#$#(&%>A#+$(@500(A#</>#(5&?5H5?%*0(.8+5&'(?*8*(58#>$(5&(83#(J+/'+*>1(=&(/+?#+(8/

*H#+*'#(83#>-(@#(@/%0?(3*H#(8/(</&H#+8(83#>(8/(?/%A0#(H*0%#$1(U+(@#(</%0?(D%$8(+#*?(83#>(*$(?/%A0#(H*0%#$(G+/>

83#(G50#1(;35$(5$($3/@&(5&(83#(#c*>J0#(A#0/@(@35<3(+#*?$(5&(83#(&%>A#+$(*A/H#(*&?(*H#+*'#$(83#>(*00(8/'#83#+1

{

// read the line

String line = inputFile.nextLine();

// output it to console

System.out.println(line);

}

} catchcatch (Exception ex)

{

// stack trace for programmer

ex.printStackTrace();

// message for user

System.out.println("Unable to continue reading from file");

} finallyfinally

{

inputFile.close();

}

44.5

33.2

-100

66.7

2345

-234256

12343256

22.7

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Page 96 of 185http://itec2150.gitlab.io/

5.9. Regular Expressions and parsing a ﬁle

l#'%0*+(#cJ+#$$5/&$(*00/@(%$(8/(#cJ*&?(83#(?#G5&585/&(/G(@3*8(83#(.<*&&#+($##$(*$(?#05>58#+$1(2#05>58#+$(*+#

<3*+*<8#+$(%$#?(A"(.<*&&#+(8/(?#8#+>5&#(@3#+#(/&#(J5#<#(/G(?*8*($8*+8$(*&?(*&/83#+(#&?$1(;3#(8"J#$(/G(?#05>58#+

*+#(/G8#&(?5<8*8#?(A"(83#(>#83/?(/G(.<*&&#+(%$#?1(V/+(#c*>J0#-(83#(>#83/?$(%$#?(8/(+#*?(*($J#<5G5<(8"J#(/G(?*8*Q

next()-(nextInt()-(nextDouble()-(#8<(%$#(@358#$J*<#(<3*+*<8#+$(A"(?#G*%081(4358#$J*<#(<3*+*<8#+$(*+#(&/&Q

J+5&85&'(<3*+*<8#+$(%$#?(8/(J+/H5?#(&#'*85H#($J*<#(/&(*(J+5&8#?(J*'#1(;3#$#(J+/H5?#(&#'*85H#(/+(r@358#r($J*<#(/&(*

importimport java.io.Filejava.io.File;

importimport java.io.IOExceptionjava.io.IOException;

importimport java.util.Scannerjava.util.Scanner;

/**

* Use with numbers.txt in default file directory Program reads the numbers.txt

* file and averages all the numbers

publicpublic classclass ReadNumbersFromFile

{

publicpublic staticstatic voidvoid main(String[] args)

{

// declare variables outside try/catch block to avoid scope issues

Scanner inputFile = nullnull;

// keep a running total of numbers read

doubledouble sum = 0;

// keep count of numbers read

intint numberCount = 0;

trytry

{

inputFile = newnew Scanner(newnew File("numbers.txt"));

whilewhile (inputFile.hasNextDouble())

{

doubledouble num = inputFile.nextDouble();

numberCount++;

sum = sum + num;

}

} catchcatch (IOException ex)

{

System.out.println("Problem reading file encountered");

ex.printStackTrace();

} finallyfinally

{

// ALWAYS close file when done

inputFile.close();

}

// computer and print average of the numbers

doubledouble average = sum / numberCount;

System.out.println("The average of the numbers read is: " + average);

}

JAVA

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Page 97 of 185http://itec2150.gitlab.io/

J+5&8#?(J*'#1(bc*>J0#$(*+#(83#(8*A(<3*+*<8#+-(83#(A0*&,($J*<#(<3*+*<8#+(*&?(83#(&#@(05&#(<3*+*<8#+1(;3#(>#83/?

nextLine()(/&0"(%$#$(83#(&#@(05&#(<3*+*<8#+(*$(*(?#05>58#+1(;3#(5&J%8(>#83/?$(@/+,(A"($,5JJ5&'(*&"(?#05>58#+$-

+#*?5&'(<3*+*<8#+$(%&850(83#(&#c8(?#05>58#+(5$(+#*<3#?1(;3#(<3*+*<8#+$(+#*?(*+#(</&H#+8#?(5&8/(83#(?#$5+#?(8"J#(*&?

+#8%+&#?1(=G(83#(<3*+*<8#+$(+#*?(?/(&/8(>*8<3(83#(?#$5+#?(8"J#(O51#1(r*A<r(5$(+#*?(@3#&(<*005&'(nextInt()R-(*&

=&J%8S5$>*8<3bc<#J85/&(5$(83+/@&1

4#(<*&(>/?5G"(83#(<3*+*<8#+$(83#(.<*&&#+(/AD#<8(%$#$(*$(?#05>58#+(A"(J*$$5&'(5&(*(.8+5&'(,&/@&(*$(*(+#'%0*+

#cJ+#$$5/&(/+(+#'#c(%$5&'(83#(.<*&&#+(>#83/?(useDelimiter(String regex)1

./>#(</>>/&0"(%$#?(+#'#c(.8+5&'$(*+#(?#G5&#?(*8B(388J$BPP@@@1D+#A#01</>PA0/'PD*H*Q+#'%0*+Q#cJ+#$$5/&$Q<3#*8Q

$3##8(1(F?H*&<#?(%$#+$(/G(+#'%0*+(#cJ+#$$5/&(@500(%$#(83#(6*H*(N5A+*+"(<0*$$(Pattern(8/(?#G5&#(</>J0#c(+#'%0*+

#cJ+#$$5/&$1(F(</>>/&($5>J0#(%$#(5$(8/(+#*?(</>>*(?#05>58#?(G50#$(05,#(83/$#($/>#85>#$('#&#+*8#?(A"

$J+#*?$3##8(J+/'+*>$1(F(</>>*(?#05>58#?(G50#(</&8*5&$(?*8*(5&(*(8#c8(G50#($#J*+*8#?(A"(*(</>>*(<3*+*<8#+1

7/>>*(<3*+*<8#+$(*+#(&/8(?#G*%08(?#05>58#+$(%$#?(A"(.<*&&#+1(4#(<*&(*??(83#(</>>*(*$(*(?#05>58#+(A"(<*005&'(83#

useDelimiter()(>#83/?(/&(.<*&&#+(*&?(J*$$5&'(5&(*(</>>*(<3*+*<8#+1(.##(83#(#c*>J0#(A#0/@(@35<3(+#*?$(5&(*

</>>*(?#05>58#?(G50#(&*>#?(`//,C1<$H1(!#+#(5$(@3*8(83#(G50#(0//,$(05,#1

=G(@#(*88#>J8(8/(+#*?(83#(CT(&%>A#+$(%$5&'(nextInt()-(@#(@500('#8(=&J%8S5$>*8<3bc<#J85/&(#*<3(85>#(*(</>>*(5$

?#8#<8#?1(`"(*??5&'(83#(</>>*(*$(*(?#05>58#+-(@#(G5c(83*8(J+/A0#>1(.##(83#(G50#(A#0/@(83*8(*??$(83#(</>>*(*$(*

?#05>58#+(*&?($%<<#$$G%00"(+#*?$(83#(CT(&%>A#+$1

1,2,3,4,5,6,7,8,9,10

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5.10. Case Study: A Client Database

N#8m$(0//,(*8(*&(#c*>J0#(/G(%$5&'(8#c8(G50#$(8/(</&8*5&(5&G/+>*85/&(*A/%8(*(A%$5&#$$m$(<05#&8(%$5&'(8#c8(G50#$(8/($8/+#

83#(5&G/+>*85/&(*&?(/AD#<8Q/+5#&8#?(J+5&<5J0#$(8/(?#$5'&(83#(*JJ05<*85/&1(j/8#(83*8(83#(<05#&8(5&G/+>*85/&(5$

>5&5>*0(G/+(J%+J/$#$(/G(A+#H58"1(4#($8*+8(A"(<+#*85&'(*(<0*$$(8/(3/0?(5&G/+>*85/&(*A/%8(*($5&'0#(<05#&81(.##(83#(<0*$$

A#0/@1(j/8#(83*8(83#(<0*$$(</&8*5&$(83+##(*88+5A%8#$(*A/%8(*(<05#&8(*&?('#88#+(>#83/?$(G/+(83#(83+##(*88+5A%8#$1(;3#

<0*$$(*0$/(5>J0#>#&8$(83#(7/>J*+*A0#(5&8#+G*<#(5&(<*$#(@#(@*&8(8/($/+8(/%+(705#&8(05$8(A"(&*>#1(F&?(83#(<0*$$

/H#++5?#$(83#(?#G*%08(8/.8+5&'OR(>#83/?(8/(J+5&8(<05#&8(5&G/+>*85/&(5&(*(%$#+QG+5#&?0"(G/+>*81

importimport java.io.Filejava.io.File;

importimport java.io.IOExceptionjava.io.IOException;

importimport java.util.Scannerjava.util.Scanner;

/**

* This example reads a set of numbers stored in a comma delimited file (.csv)

* output from Excel using regular expressions- it sums the numbers and prints

* the sum. To run properly need example file Book1.csv in default file location

publicpublic classclass ReadCSVFile

{

publicpublic staticstatic voidvoid main(String[] args)

{

Scanner inputFile = nullnull;

intint sum = 0;

// define the regular exppression

String regex = ",";

trytry

{

inputFile = newnew Scanner(newnew File("Book1.csv"));

inputFile.useDelimiter(regex);

// scanner will use the String regex to determine where one number starts

// and another ends

whilewhile (inputFile.hasNext())

{

String numString = inputFile.next();

intint num = Integer.parseInt(numString);

sum = sum + num;

System.out.println(numString);

}

} catchcatch (IOException ex)

{

ex.printStackTrace();

System.out.println("There was a problem opening or reading file");

} finallyfinally

{

inputFile.close();

}

System.out.println("The sum is : " + sum);

}

JAVA

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/**

* This class contains information about a client/customer that is maintained in

* a business's data store. The class follows good object oriented principles

* for data encapsulation and hiding.

publicpublic classclass Client implementsimplements Comparable<Client>

{

// attributes of the client

privateprivate intint clientNumber;

privateprivate String name;

privateprivate String address;

// constructor- no default constructor provided so number, name and address info

// must be provided

// at construction time. No set methods are provided to enforce this.

publicpublic Client(intint clientNumber, String name, String address)

{

thisthis.clientNumber = clientNumber;

thisthis.name = name;

thisthis.address = address;

}

// getter methods to allow information to be viewed outside the class

/**

* @return the clientNumber

publicpublic intint getClientNumber()

{

returnreturn clientNumber;

}

/**

* @return the name

publicpublic String getName()

{

returnreturn name;

}

/**

* @return the address

publicpublic String getAddress()

{

returnreturn address;

}

// compare to method to allow list of clients to be sorted if desired

@Override

publicpublic intint compareTo(Client other)

{

// compare clients based on name and if same name- use clientNumber

ifif (thisthis.name.equalsIgnoreCase(other.name))

{

// name is the same - return based on clientNumber

ifif (thisthis.clientNumber < other.clientNumber)

{

returnreturn -1;

JAVA

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j/@(@#(3*H#(8/(@+58#(83#(*JJ05<*85/&(8/(,##J(*(05$8(/G(/%+(A%$5&#$$m$(<05#&8$1(;3#(705#&82*8*A*$#(<0*$$(</&8*5&$

>#83/?$(8/(+#*?(G+/>(*(8#c8(G50#(&*>#?(r<05#&818c8r1(;3#(>#83/?(<+#*8#$(/AD#<8$(/G(8"J#(705#&8(A*$#?(/&(83#(8#c8

+#*?(5&(*&?(83#&($8/+#$(83#>(5&(*&(F++*"N5$81(=&(*JJ05<*85/&$(05,#(835$-(58(5$(</>>/&(8/(3*+?(</?#(83#(8#c8(G50#(&*>#

$5&<#(83#(A%$5&#$$(J+/A*A0"(5$(&/8('/5&'(8/(<3*&'#1(4#(*0$/(3*H#(*(>#83/?(8/(@+58#(*&(F++*"N5$8(/G(705#&8(/AD#<8$(8/

83#($*>#(8#c8(G50#1(`"(%$5&'(83#($*>#(8#c8(G50#(&*>#-(@#(@500(?#0#8#(83#(/0?(?*8*(*&?(@+58#(83#(&#@1(;3#+#(*+#(*0$/

>#83/?$(8/(J+5&8(*(%$#+(>#&%(*&?(*&/83#+(8/(J+/>J8(G/+(*&?(+#*?(5&(83#(5&G/+>*85/&(8/(*??(*(&#@(705#&8(/AD#<8(8/

83#(?*8*A*$#1(`"(<+#*85&'($#J*+*8#(>#83/?$(8/(?/(83#$#(8*$,$-(@#(A+#*,(83#(J+/A0#>(%J(5&8/($>*00#+(#*$5#+(8/($/0H#

J+/A0#>$1(=8(*0$/(>*,#$(83#(</?#(>/+#(>/?%0*+-(+#*?*A0#(*&?(+#%$*A0#1(.##(83#(</?#(A#0/@1

} elseelse ifif (thisthis.clientNumber > other.clientNumber)

{

returnreturn 1;

} elseelse

// they must be equal if none of above is true

{

returnreturn 0;

}

} elseelse

// names are not equal- use String compareTo to determine greater than, less

// than or equal

{

returnreturn thisthis.name.compareTo(other.name);

}

// provide a toString method to print client information in easy to read fashion

@Override

publicpublic String toString()

{

returnreturn "clientNumber=" + clientNumber + "\nname=" + name + "\naddress=" + address + "\n";

}

importimport java.io.Filejava.io.File;

importimport java.io.FileNotFoundExceptionjava.io.FileNotFoundException;

importimport java.io.PrintWriterjava.io.PrintWriter;

importimport java.util.ArrayListjava.util.ArrayList;

importimport java.util.Scannerjava.util.Scanner;

/**

* This class reads data from textfile named client.txt and uses it to populate

* an ArrayList of Client objects. The user is then able to change the ArrayList

* by deleting or adding an object. Upon exit, the client.txt file is

* overwritten with the modified ArrayList

publicpublic classclass ClientDatabase

{

* This method reads in client.txt, creates Client objects based on the data,

* and populates theList with the new Client objects

* @param ArrayList<Client>

* @return ArrayList<Client>

JAVA

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publicpublic ArrayList<Client> readFile(ArrayList<Client> theList)

{

String fileName = "client.txt";

// hard coding file name

File theFile = nullnull;

Scanner inputFile = nullnull;

trytry

{

theFile = newnew File(fileName);

inputFile = newnew Scanner(theFile);

} catchcatch (FileNotFoundException ex)

{

System.out.println("Unable to open client file- continuing with empty list");

returnreturn theList;

}

// file opened- now let's read from it

trytry

{

whilewhile (inputFile.hasNextLine())

// loop until we get to end of the file

{

// first read client Number as String- mixing reading Strings and ints

// causes issues- so read as String and convert

String number = inputFile.nextLine();

intint clientNumber = Integer.parseInt(number);

// now name

String name = inputFile.nextLine();

// now address

String address = inputFile.nextLine();

// now create Client object and add to ArrayList

Client c = newnew Client(clientNumber, name, address);

theList.add(c);

}

} catchcatch (Exception ex)

{

ex.printStackTrace();

System.out.println("Problem reading the client file- continuing with what was read");

} finallyfinally

{

inputFile.close();

}

returnreturn theList;

}

* This method takes the Client objects in theList and converts them to the

* proper format for writing in to the client.txt file. Note existing contents

* of client.txt are overwritten.

* @param theList

publicpublic voidvoid writeFile(ArrayList<Client> theList)

{

// variable for file name

String fileName = "client.txt";

// variable to hold info about the File

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File theFile;

// PrintWriter object to open for writing to file

PrintWriter outputFile = nullnull;

trytry

{

theFile = newnew File(fileName);

outputFile = newnew PrintWriter(theFile);

} catchcatch (FileNotFoundException ex)

{

System.out.println("Unable to write client.txt in default location- check file permissions and try

again");

// print stack trace for debugging - remove when program is working properly

ex.printStackTrace();

}

// now write to and close the file

trytry

{

// loop through the entries in ArrayList

forfor (intint i = 0; i < theList.size(); i++)

{

// get a local variable to shorten typing

Client c = theList.get(i);

// format of file = clientNumber, name, address - each on own line

outputFile.println(c.getClientNumber());

outputFile.println(c.getName());

outputFile.println(c.getAddress());

}

} catchcatch (Exception ex)

// using exception instead of specific exception because many possible wrong

// things could happen

{

ex.printStackTrace();

// print the stack trace for debug purposes.

} finallyfinally

{

outputFile.close();

}

/**

* Method to print the user menu to console

publicpublic voidvoid printMenu()

{

System.out.println("a. View Client List");

System.out.println("b. Add a Client");

System.out.println("c. Delete a Client");

System.out.println("d. Quit");

}

/**

* Method to prompt user to enter info for new Client

* @param Scanner

* @return Client

publicpublic Client addClient(Scanner s)

{

System.out.println("Please enter client number");

4/5/21, 10)50 PMIntermediate Programming

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intint number = s.nextInt();

// read extra delimiter left from reading in a number

s.nextLine();

System.out.println("Enter client name");

String name = s.nextLine();

System.out.println("Enter client address");

String address=s.nextLine();

Client c = newnew Client(number, name, address);

returnreturn c;

}

/**

* The main method

* @param args

publicpublic staticstatic voidvoid main(String[] args)

{

// create scanner to read from console

Scanner keyboard = newnew Scanner(System.in);

// create an instance of this class to use non-static methods

ClientDatabase theClass = newnew ClientDatabase();

// create array list for client list and then read file

ArrayList<Client> theClientList = newnew ArrayList<Client>();

// call method to read file

theClientList = theClass.readFile(theClientList);

booleanboolean keepLooping = truetrue;

// loop until user wants to quite

whilewhile (keepLooping)

{

// print the menu

theClass.printMenu();

String choice = keyboard.nextLine();

ifif (choice.equalsIgnoreCase("a"))

{

// print the database

forfor (Client c: theClientList)

{

System.out.println(c);

}

elseelse ifif (choice.equalsIgnoreCase("b"))

{

// add a client

theClientList.add(theClass.addClient(keyboard));

}

elseelse ifif (choice.equalsIgnoreCase("c"))

{

// delete a client

System.out.println("Enter client number to delete");

// read as String to avoid delimiter issues

String num = keyboard.nextLine();

intint clientNumber = Integer.parseInt(num);

// find record in arrayList wiht matching client number and delete it

forfor (intint i = 0; i< theClientList.size(); i++)

4/5/21, 10)50 PMIntermediate Programming

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5.11. Key Terms

V50#(Q(F(+#$/%+<#(%$#?(8/($8/+#(*(</00#<85/&(/G(?*8*(/&(*(</>J%8#+($8/+*'#(?#H5<#1

;#c8(V50#(Q(F(</>J%8#+(G50#(</&$5$85&'(/G(3%>*&(+#*?*A0#(Z&5</?#(<3*+*<8#+$1(;"J5<*00"(+#*?(%$5&'(*(8#c8(#?58/+(05,#

83#(/&#(5&(>/$8(=2bm$1(7/&$5?#+#?(3%>*&(+#*?*A0#1

`5&*+"(V50#(Q(F(</>J%8#+(G50#($8/+#?(5&(83#(&*85H#(A5&*+"(</?#(/G(83#(</>J%8#+1(j/8(</&$5?#+#?(3%>*&(+#*?*A0#1

=&J%8(Q(=&G/+>*85/&(/+(?*8*(G+/>(*&(#c8#+&*0($/%+<#(+#*?(5&8/(*(6*H*(J+/'+*>1

U%8J%8(Q(=&G/+>*85/&(/+(?*8*(G+/>(*(6*H*(J+/'+*>(@+588#&(8/(*&(#c8#+&*0($/%+<#1

UJ#&(*(V50#Q(7+#*8#(*($8+#*>(/G(?*8*(8/(/+(G+/>(*(</>J%8#+(G50#1

V50#(.8+#*>(Q(F(/&#(@*"(d%#%#(/G(?*8*(#583#+(8/(/+(G+/>(*(G50#1(;3#(/+?#+(/G(?*8*(5&(83#(d%#%#(+#J+#$#&8$(83#(/+?#+

/G(83#(?*8*(5&(83#(G50#1

70/$#(*(V50#Q(V0%$3(*&?(<0/$#(*($8+#*>(/G(?*8*(8/(/+(G+/>(*(G50#1(43#&(@+585&'(*(G50#-(G/+<#$(83#(J+/'+*>(8/(@*58(%&850

*00(?*8*(5&(83#($8+#*>(3*$(A##&(@+588#&(8/(83#(G50#1(43#&(+#*?5&'(*(G50#-(8#+>5&*8#$(*&"(G%+83#+(?*8*(</>5&'(G+/>

83#(G50#1

{

Client c = theClientList.get(i);

ifif (c.getClientNumber() == clientNumber)

{

theClientList.remove(i);

System.out.println("Client removed");

breakbreak;

// stop searching once found

}

elseelse

//if a, b or c not chosen- end loop

{

keepLooping = falsefalse;

}

// write back to file

System.out.println("Writing new client list to file");

theClass.writeFile(theClientList);

}

4/5/21, 10)50 PMIntermediate Programming

Page 105 of 185http://itec2150.gitlab.io/

2#05>58#+(Q(2#05>58#+$(*+#(@358#$J*<#(<3*+*<8#+$(%$#?(8/($#J*+*8#(H*+5/%$(J5#<#$(/G(?*8*(5&(*(8#c8(G50#1(bc*>J0#$(*+#

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5.12. Exercises

5.12.1. Exercise 1

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5&(83#(G/00/@5&'(G/+>*8(@3#+#(ccc(+#J+#$#&8$(*(&%>A#+(<*0<%0*8#?(*A/H#1

5.12.2. Exercise 2

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J+/'+*>($3*00(83#&(/J#&(*(8#c8(G50#(&*>#?(J/#>$18c8(G/+(@+585&'(*&?(@+58#(83#(5&G/+>*85/&(*A/%8(#*<3(J/#>(8/(83#

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/&(*(05&#(*&?(83#&(83#(J/#8(&*>#(/&(*($#</&?(05&#(G/+(#*<3(J/#>1

The sum of the numbers is: xxx

The lowest number is: xxx

The highest number is : xxx

The average of the numbers is : xxx

/**

* Poem.java

* A class representing information about a poem for use in Chapter 5 Exercise 2

publicpublic classclass Poem

{

privateprivate String name;

privateprivate String poet;

/**

* no-arg constructor

publicpublic Poem()

{

// initialize attributes

name = "unknown";

poet = "unknown";

}

/**

* @return the name

publicpublic String getName()

{

returnreturn name;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 106 of 185http://itec2150.gitlab.io/

5.12.3. Exercise 3

Z$5&'(83#()/#>(<0*$$('5H#&(5&(#c#+<5$#(E-(@+58#(*(6*H*(J+/'+*>(8/(+#*?(G+/>(*(8#c8(G50#(&*>#?(J/#>E18c8(J+/H5?#?

A#0/@1(;3#(J+/'+*>($3*00(+#*?(83#(&*>#(*&?(J/#8(/G(#*<3(J/#>-(<+#*8#(*&(/AD#<8(/G(8"J#()/#>(G/+(#*<3(&*>#PJ/#8

J*5+(*&?(J+5&8(*00(83#(+#*?(J/#>(5&G/+(8/(83#(</&$/0#1

5.13. Issue Tracker/Comments

=$$%#(;+*<,#+ O388J$BPP'583%A1</>P3J*+,WP3#0JY?#$,P5$$%#$R

/**

* @param name the name to set

publicpublic voidvoid setName(String name)

{

thisthis.name = name;

}

/**

* @return the poet

publicpublic String getPoet()

{

returnreturn poet;

}

/**

* @param poet the poet to set

publicpublic voidvoid setPoet(String poet)

{

thisthis.poet = poet;

}

@Override

publicpublic String toString()

{

returnreturn "Poem [name=" + name + ", poet=" + poet + "]";

}

We Real Cool

Gwendolyn Brooks

I Know Why the Caged Bird Sings

Maya Angelou

Hope is the Thing with Feathers

Emily Dickinson

The Road Not Taken

Robert Frost

4/5/21, 10)50 PMIntermediate Programming

Page 107 of 185http://itec2150.gitlab.io/

6. Generics

6.1. Learning Outcomes

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6.2. Resources

6.2.1. Text

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6.2.2. Videos

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6.3. Introduction

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q#&#+5<(S#83/?$

4/5/21, 10)50 PMIntermediate Programming

Page 108 of 185http://itec2150.gitlab.io/

l*@(;"J#$(*&?(`*<,@*+?(7/>J*85A5058"

450?<*+?(q#&#+5<(;"J#$

b+*$%+#

6.4. Motivations and Beneﬁts

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>#83/?(J+5&8.%>(*88#>J8$(8/(<*$8(83#($8+5&'(8/(*&(5&8#'#+(5&(83#($8*8#>#&8($%>(v](O=&8#'#+R(5e(5&(/+?#+(8/(</>J%8#

83#($%>(/G(*00(#0#>#&8$(@35<3(*+#(#cJ#<8#?(8/(A#(5&8#'#+$1

//before JDK 1.5

importimport java.util.ArrayListjava.util.ArrayList;

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

ArrayList list = newnew ArrayList();

//<-- ArrayList without generic called raw type

list.add(67);

list.add(56);

list.add(4);

list.add("Straweberry");

//<-- it will throw the ClassCastException

list.add(52);

printSum(list);

}

privateprivate staticstatic voidvoid printSum(ArrayList n)

{

Integer sum = 0;

forfor(Object i: n)

{

//ArrayList (java.util.ArrayList) has the Object as a type

sum += (Integer)i;

//You need to type cast these to each particular data type every time

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 109 of 185http://itec2150.gitlab.io/

;3#(G/00/@5&'(<0*$$(?#>/&$8+*8#$(83#(%$#(/G(*(J*+*>#8+5a#?(8"J#(F++*"N5$8x=&8#'#+y(/G(83#('#&#+5<(<0*$$

F++*"N5$8x;y1(!#+#(83#(</&<+#8#(*+'%>#&8(8"J#(=&8#'#+(8*,#$(83#(J0*<#(/G(83#(G/+>*0(8"J#(J*+*>#8#+(;(5&(83#

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5&$8*&<#(/G(83#(=&8#'#+(<0*$$1(;3#+#(5$(&/(&##?(8/(<*$8(@3#&(%$5&'(83#(#0#>#&8$(*$(5&8#'#+$1(43#&(/&#(*88#>J8$(8/

*??(*(&/&Q=&8#'#+(/AD#<8(O#1'1(*($8+5&'R(8/(83#(05$8-(83#(</>J50#+(@500('#&#+*8#(*&(#++/+1

N#8m$(0//,(*8(*&/83#+($<#&*+5/1(43*8(5G("/%(@*&8(8/(?#H#0/J(*(</&8*5&#+

O388J$BPP@@@1/+*<0#1</>P8#<3&5<*0Q+#$/%+<#$P*+85<0#$PD*H*PD%&#*%Q'#&#+5<$138>0R(83*8(3*$(83#(*A5058"(8/(3/0?(/AD#<8$(/G(H*+5/%$

8"J#$\(V5+$8-("/%(<+#*8#(*(7/&8*5&#+(<0*$$(*$(A#0/@1

//Since JDK 1.5 - this example shows how the generic types can be used.

importimport java.util.ArrayListjava.util.ArrayList;

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

ArrayList<Integer> list = newnew ArrayList<>();

// <-- ArrayList with generic

list.add(67);

list.add(56);

printSum(list);

}

privateprivate staticstatic voidvoid printSum(ArrayList<Integer> n)

{

intint sum = 0;

forfor(intint i: n){

sum += i;

}

JAVA

Basic form to create an instance of generic classclass

BaseType<Type> object = newnew BaseType<Type>();

For the type argument, we cannot use a primitive type (e.g. intint, charchar, doubledouble, booleanboolean).

JAVA

publicpublic classclass Container

{

privateprivate Object obj;

publicpublic Object getObj()

{

returnreturn obj;

}

publicpublic voidvoid setObj(Object obj)

{

thisthis.obj = obj;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 110 of 185http://itec2150.gitlab.io/

;3#(G/00/@5&'(ContainerWithoutGenerics(<0*$$(%$#$(*(</&8*5&#+(8/($8/+#(*&?(+#8+5#H#(H*0%#$1(;3#(>*5&(>#83/?

<+#*8#$(*(</&8*5&#+(*&?($8/+#$(EI-(r6*H*r(*&?(KL1^[(5&(835$(/+?#+1(./(&/@(KL1^[(5$(83#($8/+#?(H*0%#1(;3#&("/%(&##?(8/

%$#(*&(#cJ05<58(<*$8(8/(+#8+5#H#(83#(H*0%#1

=&(</&8+*$8-(83#(G/00/@5&'(Container(<0*$$(%$#$(*('#&#+5<(8"J#(;1(=&(83#(8"J#(J*+*>#8#+($#<85/&(x;y-(83#(*&'0#

A+*<,#8$(#&<0/$#(83#(G/+>*0(8"J#(J*+*>#8#+(;1

;3#(>*5&(>#83/?(/G(83#(ContainerTester(<0*$$(<+#*8#$(*(</&8*5&#+(/AD#<8(/G(83#(J*+*>#8+5a#?(<0*$$

Container<String>-(*&?($8/+#$(?5GG#+#&8(8"J#$(/G(H*0%#$(8/(83#(</&8*5&#+1(;3#($8*8#>#&8(string.setObj(10.56)(@500

<*%$#(*(</>J50*85/&(#++/+(*$(*(+#$%08(/G(8"J#Q<3#<,5&'1

importimport java.util.ArrayListjava.util.ArrayList;

importimport java.util.Listjava.util.List;

publicpublic classclass ContainerWithoutGenerics

{

publicpublic staticstatic voidvoid main(String[] args)

{

Container obj = newnew Container();

obj.setObj(23);

//store an int which is autoboxed to an Integer object

obj.setObj("Java");

//then store a string

obj.setObj(45.98);

//then store an double which is autoboxed to a Double object - current value

List list = newnew ArrayList();

list.add(obj);

Double doubleValue = (Double)((Container)list.get(0)).getObj();

//current value is a double value

System.out.println("doubleValue: " + doubleValue);

}

JAVA

publicpublic classclass Container<T>

{

privateprivate T obj;

publicpublic T getObj()

{

returnreturn obj;

}

publicpublic voidvoid setObj(T obj)

{

thisthis.obj = obj;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 111 of 185http://itec2150.gitlab.io/

V/00/@5&'(<0*$$(O*R(5$(8/(5?#&85G"(5G(*(J#+$/&O#1'1(6/#-(6#$$#R(5$(*&(#>J0/"##(/G(<0*$$#$B(Microsoft, Apple, Google, or

Adobe1(;3#(J%+J/$#(/G(83#(J+/'+*>(5$(8/(>*,#($%+#(/&0"(</++#<8(Company(8"J#(@3#+#(83#(#>J0/"##(5$(@/+,5&'1

!/@#H#+-(#H#&(83/%'3(Google(/AD#<8(&*>#?(joe(5$(<+#*8#?(A%8("/%($8500(<*&(*??(joe(8/(83#(</>J*&"(Apple(*&?(OAR

5$(8/($3/@(3/@('#&#+5<(<0*$$((Company<T>)(5$(%$#G%0(8/(G5c(83#(A%'(G+/>(83#(</?#(O*R1=G("/%($##(Main(<0*$$OAR-("/%

/&0"(<*&(*??(#>J0/"##$(G+/>(</++#<8(</>J*&"1(=G(_ Jesse_(5$(*&(#>J0/"##(/G(Microsoft, addEmployee()(<*&(/&0"

8*,#(Jesse1

publicpublic classclass ContainterTester

{

publicpublic staticstatic voidvoid main(String[] args)

{

Container<String> string = newnew Container<String>();

string.setObj("Cupertino");

//Correct type value - String

string.setObj(10.56);

//won't compile because 10.56 is not a string value but a double value.

}

JAVA

importimport java.util.ArrayListjava.util.ArrayList;

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

{

Google joe = newnew Google("Joe");

// Joe is an employee of Google

Microsoft jesse = newnew Microsoft("Jesse");

Adobe bill = newnew Adobe("Bill");

Company google = newnew Company("Google");

google.addEmployee(joe);

google.addEmployee(jesse);

Company apple = newnew Company("Apple");

apple.addEmployee(joe);

//joe is an object of Google not Apple but still you can pass joe in

addEmployee().

apple.addEmployee(bill);

}

classclass Employee

{

privateprivate String name;

publicpublic Employee(String name)

{

thisthis.name = name;

}

publicpublic String getName()

{

returnreturn name;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 112 of 185http://itec2150.gitlab.io/

}

classclass Google extendsextends Employee

{

publicpublic Google(String name) {

//name is an employee name

supersuper(name);

}

classclass Adobe extendsextends Employee

{

publicpublic Adobe(String name)

{

supersuper(name);

}

classclass Company

{

privateprivate String name;

privateprivate ArrayList<Employee> eList = newnew ArrayList<>();

publicpublic Company(String name)

{

thisthis.name = name;

}

publicpublic String getName()

{

returnreturn name;

}

publicpublic booleanboolean addEmployee(Employee employee)

{

ifif(eList.contains(employee))

{

System.out.println(employee.getName() + " is already confirmed as an employee of " +

thisthis.name);

returnreturn falsefalse;

}

elseelse {

eList.add(employee);

System.out.println(employee.getName() + " is an employee of " + thisthis.name);

returnreturn truetrue;

}

classclass Microsoft extendsextends Employee

{

publicpublic Microsoft(String name){

//name is an employee name

supersuper(name);

}

importimport java.util.ArrayListjava.util.ArrayList;

publicpublic classclass Main

{

publicpublic staticstatic voidvoid main(String[] args)

4/5/21, 10)50 PMIntermediate Programming

Page 113 of 185http://itec2150.gitlab.io/

{

Google joe = newnew Google("Joe");

Microsoft jesse = newnew Microsoft("Jesse");

Adobe bill = newnew Adobe("Bill");

Company<Google> google = newnew Company("Google");

google.addEmployee(joe);

//google.addEmployee(jesse);

//jesse is an object of Microsoft so you cannot pass jesse in addEmployee() when it is called by google.

(1)

//google.addEmployee(bill); //same reason. (2)

Company<Microsoft> microsoft = newnew Company("Microsoft");

microsoft.addEmployee(jesse);

// microsoft.addEmployee(bill); //same reason (3)

//microsoft.addEmployee("Bill"); //(4) you also cannot pass a string to addPlayer() method.

}

classclass Employee

{

privateprivate String name;

publicpublic Employee(String name)

{

thisthis.name = name;

}

publicpublic String getName()

{

returnreturn name;

}

classclass Google extendsextends Employee

{

publicpublic Google(String name)

{

//name is an employee name

supersuper(name);

}

classclass Adobe extendsextends Employee

{

publicpublic Adobe(String name)

{

supersuper(name);

}

classclass Company<T>

{

privateprivate String name;

privateprivate ArrayList<T> eList = newnew ArrayList<>();

publicpublic Company(String name)

{

thisthis.name = name;

}

publicpublic String getName()

4/5/21, 10)50 PMIntermediate Programming

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=&(835$(J+/'+*>(A-(@3#&("/%(?#<0*+#(google.addEmployee(jesse) or google.addEmployee(bill) or

microsoft.addEmployee(bill)(A"(8+"5&'(8/(J*$$(5&</++#<8(8"J#(/AD#<8(/+(microsoft.addEmployee("Bill")(A"

8+"5&'(8/(J*$$(*($8+5&'(r`500r-(D*H*(@500($3/@(#++/+$(O$##(OCR-OER-OIR-OKRR1(;35$(5$(@3*8(@#(3*H#(?#G5&#?(83#

addEmployee()(>#83/?(5&(Company<T>(O$##(<1(A#0/@R1(./(83#(Company<T>(<0*$$(+#d%5+#(%$(8/(%$#(b>J0/"##

<0*$$(/+(*($%A<0*$$(/G(Employee1(F&?(*0$/(.8+5&'(8"J#(J*+*>#8#+(5$(&/8(8*,#&(G+/>(83#(addEmployee()(>#83/?1

=&$8#*?-(58(5$(8*,5&'('#&#+5<(8"J#(/AD#<8O;(#>J0/"##R1

{

returnreturn name;

}

publicpublic booleanboolean addEmployee(T employee)

{

ifif(eList.contains(employee))

{

System.out.println((((Employee)employee).getName() + " is already confirmed as an employee of " +

thisthis.name));

returnreturn falsefalse;

}

elseelse

{

eList.add(employee);

System.out.println((((Employee)employee).getName() + " is an employee of " + thisthis.name));

returnreturn truetrue;

}

classclass Microsoft extendsextends Employee

{

publicpublic Microsoft(String name)

{

supersuper(name);

}

publicpublic booleanboolean addEmployee(T employee)

{

ifif(eList.contains(employee))

{

System.out.println((((Employee)employee).getName() + " is already confirmed as an employee of " +

thisthis.name));

returnreturn falsefalse;

}

elseelse

{

eList.add(employee);

System.out.println((((Employee)employee).getName() + " is an employee of " + thisthis.name));

returnreturn truetrue;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 115 of 185http://itec2150.gitlab.io/

=&(*(&%8$3#00-(83#(,#"(A#&#G58(/G('#&#+5<$(5$(8/(#&*A0#(#++/+$(8/(A#(?#8#<8#?(*8(</>J50#(85>#(+*83#+(83*&(*8(+%&85>#

O#&$%+5&'(</>J50#Q85>#($*G#8"R1(F('#&#+5<(<0*$$(/+(>#83/?(J#+>58$("/%(8/($J#<5G"(*00/@*A0#(8"J#$(/G(/AD#<8$(83*8(83#

<0*$$(/+(>#83/?(<*&(@/+,(@5831(=G("/%(*88#>J8(8/(%$#(*&(5&</>J*85A0#(/AD#<8-(83#(</>J50#+(@500(?#8#<8(83*8(#++/+1

q#&#+5<$(*0$/(3#0J$(8/(+#%$#(83#(</?#(G/+(*&"(8"J#(@#(@*&8(8/(%$#1

6.5. Deﬁning Generic Classes

F$("/%(3*H#($##&(G+/>(>%085J0#(#c*>J0#$(*A/H#-(3#+#(5$(*($5>J0#(#c*>J0#(/G(?#G5&5&'(q#&#+5<(<0*$$B

GenericClass<T>(*&?(*(8#$8#+(J+/'+*>1

6.5.1. Type Parameters/Type Variables

r;"J#(J*+*>#8#+$(O*1,1*1(8"J#(H*+5*A0#$R(*+#(%$#?(*$(J0*<#3/0?#+$(8/(5&?5<*8#(83*8(*(8"J#(@500(A#(*$$5'&#?(8/(83#

<0*$$(*8(+%&85>#1rO6%&#*%-(ETCKR

`"(</&H#&85/&-(8"J#(J*+*>#8#+$(*+#(*($5&'0#(%JJ#+<*$#1(V/00/@5&'(05$8(5$(83#($8*&?*+?(8"J#(J*+*>#8#+$B

/**

* Class:GenericClass

* @param <T>

//Use <> to specify parameter type and define generic class

publicpublic classclass GenericClass<T>

{

//Type T reference variable named object declaration.

T object;

//constructor

GenericClass(T object)

{

thisthis.object = object;

}

publicpublic T getObject()

{

returnreturn thisthis.object;

}

publicpublic classclass Main {

publicpublic staticstatic voidvoid main(String[] args)

{

GenericClass<String> stringObject = newnew GenericClass<String>("\"String Value and check constructor

param\"");

System.out.println(stringObject.getObject());

GenericClass<Integer> integerObject = newnew GenericClass<Integer>(23);

// unboxing of new Integer(23);

System.out.println(integerObject.getObject());

}

JAVA

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Page 116 of 185http://itec2150.gitlab.io/

bB(b0#>#&8

_B(_#"

jB(j%>A#+

;B(;"J#

hB(h*0%#

.-Z-h(5&(*(>%085J*+*>#8#+($58%*85/&1

6.5.2. How to Use Generics?

C1( 7+#*8#(*('#&#+5<(<0*$$B(J%A05<(<0*$$(q#&#+5<70*$$x;y(z({|(}

E1( =&$8*&85*8#(83#(/AD#<81(b*<3(/G(;"J#(J*+*>#8#+(O5&(835$(<*$#-(58(5$(;R(5$(+#J0*<#?(@583(83#(=&8#'#+(8"J#1

q#&#+5<70*$$x=&8#'#+y(5&8#'#+UAD#<8(](&#@(q#&#+5<70*$$x=&8#'#+yORe

I1( q#&#+5<$(<*&(*0$/(A#(%$#?(@5835&(</&$8+%<8/+$(8/(J*$$(8"J#(J*+*>#8#+$(G/+(<0*$$(G5#0?(5&585*05a*85/&1

q#&#+5<70*$$(/AC(](&#@(q#&#+5<70*$$OIRe(q#&#+5<70*$$(/AE(](&#@(q#&#+5<70*$$Orq#/+'5*rRe

K1( q#&#+5<$(3*$(+*@(8"J#(G/+(A*<,@*+?(</>J*85A5058"1(=8(@500(#05>5&*8#(8"J#Q<3#<,5&'(*8(</>J50#(85>#1

q#&#+5<70*$$(+*@l#G(](&#@(q#&#+5<70*$$ORe

L1( q#&#+5<$(?/#$(&/8($%JJ/+8($%AQ8"J5&'(N5$8xj%>A#+y(&%>A#+$(](&#@(F++*"N5$8x=&8#'#+yORe(PP@/&m8(</>J50#1

=&8#'#+(5$*($%A8"J#(/G(j%>A#+1(N5$8x=&8#'#+y(&%>A#+$(](&#@(F++*"N5$8x=&8#'#+yORe

6.5.3. Deﬁning Generic Interfaces

!#+#(*+#(8@/(#c*>J0#$(/G(%$5&'('#&#+5<$(@583(5&8#+G*<#$(N5$8(*&?(=8#+*8/+

O388J$BPP?/<$1/+*<0#1</>PD*H*$#P8%8/+5*0P#c8+*P'#&#+5<$P$5>J0#138>0R(5&(83#(J*<,*'#(D*H*1%850B

6.6. Generic Methods

F$("/%(?#G5&#('#&#+5<(<0*$$#$-(*&?(5&8#+G*<#$-("/%(<*&(*0$/(%$#('#&#+5<(8"J#$(8/(?#G5&#('#&#+5<(>#83/?$1(;/(?#<0*+#

*('#&#+5<(>#83/?(&*>#?(print()-("/%(J0*<#(83#('#&#+5<(8"J#(xby(*G8#+(83#(,#"@/+?($8*85<(5&(83#(>#83/?(3#*?#+

*&?($8*85<(O<0*$$R(*&?(&/&Q$8*85<(O5&$8*&<#R(>#83/?$(*+#(*00/@#?1

publicpublic interfaceinterface List<E>

{

voidvoid add(E x);

Iterator<E> iterator();

}

publicpublic interfaceinterface Iterator<E>

{

E next();

booleanboolean hasNext();

}

JAVA

publicpublic staticstatic <E> voidvoid print(E[] list) {

//... }

JAVA

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Page 117 of 185http://itec2150.gitlab.io/

V/00/@5&'(j/&q#&#+5<S#83/?2#>/(J+/'+*>(3*$(/H#+0/*?#?(J+5&8OR(>#83/?$(8/(J+5&8(?5GG#+#&8(8"J#$(/G(*++*"$

O=&8#'#+-(2/%A0#-(73*+*<8#+-(*&?(.8+5&'R1

publicpublic classclass NonGenericMethodDemo

{

publicpublic staticstatic voidvoid main(String[] args)

{

// create arrays of Integer, Double, Character, and String

Integer[] integerArray = {1, 2, 3, 4};

Double[] doubleArray = {2.1, 22.2, 31.65, 10.5};

Character[] characterArray = {'G', 'E', 'N', 'E', 'R','I','C','S'};

String[] stringArray = {"Lawrenceville", "Duluth", "Chicago", "New York", "Atlanta"} ;

System.out.println("Array integerArray contains:");

print(integerArray);

// pass an Integer array

System.out.println("Array doubleArray contains:");

print(doubleArray);

// pass a Double array

System.out.println("Array characterrArray contains:");

print(characterArray);

// pass a Character array

System.out.println("Array stringArray contains:");

print(stringArray);

// pass a Character array

}

/**

* method print to print Integer array

* @param arr

publicpublic staticstatic voidvoid print(Integer[] arr)

{

// display array elements

forfor (Integer element : arr)

System.out.print(element + " ");

System.out.println();

}

/**

* method print to print Double array

* @param arr

publicpublic staticstatic voidvoid print(Double[] arr)

{

// display array elements

forfor (Double element : arr)

System.out.print(element + " ");

System.out.println();

}

/**

* method print to print Character array

* @param arr

publicpublic staticstatic voidvoid print(Character[] arr)

{

// display array elements

forfor (Character element : arr)

System.out.print(element + " ");

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 118 of 185http://itec2150.gitlab.io/

4350#(#*<3(print()(>#83/?(*A/H#(5$(@+588#&(G/+(*(?5GG#+#&8(?*8*(8"J#-(83#5+(</?#(5$(/83#+@5$#(5?#&85<*0(*&?(%$#$(*

G/+Q#*<3(0//J(8/(?5$J0*"(*++*"(#0#>#&8$1(`"(%$5&'('#&#+5<$-(@#(<*&(@+58#(*($5&'0#('#&#+5<(print()(>#83/?(G/+(*00

?*8*(8"J#$(@583(*('#&#+5<(8"J#(b1(;3#(3#*?#+(/G(83#('#&#+5<(>#83/?(5$(J%A05<($8*85<(xby(H/5?(print(E[] arr)1(F

</>J0#8#(GenericMethodDemo(J+/'+*>(5$(J+/H5?#?(*$(G/00/@$1(`*$#?(/&(83#(8"J#$(/G(83#(*+'%>#&8$(J*$$#?(8/

83#('#&#+5<(>#83/?-(83#(</>J50#+(3*&?0#$(#*<3(>#83/?(<*00(*JJ+/J+5*8#0"1(;3#(/%8J%8$(/G(GenericMethodDemo

*&?(MethodWithoutGenerics(*+#(5?#&85<*01

System.out.println();

}

/**

* method print to print String array

* @param arr

publicpublic staticstatic voidvoid print(String[] arr)

{

forfor(String element: arr){

System.out.print(element + " ");

}

publicpublic classclass GenericMethodDemo

{

publicpublic staticstatic voidvoid main(String[] args)

{

// create arrays of Integer, Double, Character, and String

Integer[] integerArray = {1, 2, 3, 4};

Double[] doubleArray = {2.1, 22.2, 31.65, 10.5};

Character[] characterArray = {'G', 'E', 'N', 'E', 'R','I','C','S'};

String[] stringArray = {"Lawrenceville", "Duluth", "Chicago", "New York", "Atlanta"} ;

System.out.println("Array integerArray contains:");

print(integerArray);

// pass an Integer array

System.out.println("Array doubleArray contains:");

print(doubleArray);

// pass a Double array

System.out.println("Array characterrArray contains:");

print(characterArray);

// pass a Character array

System.out.println("Array stringArray contains:");

print(stringArray);

// pass a Character array

}

publicpublic staticstatic <E> voidvoid print(E[] arr)

{

// System.out.println(Arrays.toString(list));

forfor(E element: arr)

{

System.out.print(element + " ");

}

System.out.println();

}

JAVA

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Page 119 of 185http://itec2150.gitlab.io/

6.6.1. The Bounded Generic Type

F('#&#+5<(8"J#(<*&(A#($J#<5G5#?(*$(*($%A8"J#(/G(*&/83#+($%J#+<0*$$(8"J#1(;35$($%A8"J#(5$(<*00#?(A/%&?#?1(N#8m$($*"(5G

"/%(@*&8(8/(+#$8+5<8(83#(8"J#$(83*8(<*&(A#(%$#?(*$(8"J#(*+'%>#&8$(5&(*(J*+*>#8+#+5a#?(8"J#1(=8(>*"(A#(>/+#(<0#*+(8/

,&/@(3/@(8/(?#<0*+#(*(A/%&?#?(8"J#(J*+*>#8#+1(V5+$8-(05$8(83#(8"J#(J*+*>#8#+m$(&*>#(G/00/@#?(A"(83#(#c8#&?$

,#"@/+?(*&?(A"(58$(%JJ#+(A/%&?(/+($%J#+<0*$$1(V/+(#c*>J0#-(5G(*(>#83/?(/J#+*8#$(/&(&%>A#+$-("/%(>*"(@*&8(8/

>*,#(58(/&0"(*<<#J8(5&$8*&<#$(/G(j%>A#+(/+(58$($%A<0*$$#$(05,#(x;(#c8#&?$(j%>A#+y

=G("/%($##(OCR(G+/>(A(O$##(A#0/@R-(Company(<0*$$(8*,#$(*('#&#+5<(8"J#(;(J*+*>#8#+(*&?(835$(#c*>J0#($3/@$(83*8(@#

<*&(%$#(*($5&'0#(A/%&?(@3#&(@#($J#<5G"(83#(Company(8"J#(;(J*+*>#8#+1(./(58(5$(+#$8+5<85&'(7/>J*&"(8/(A#5&'

<+#*8#?(G/+(/AD#<8$(83*8(8"J#(;(5$(5&3#+58#?(G+/>(83#(b>J0/"##(<0*$$(/+($/>#(<0*$$(/G(#>J0/"##(/&0"1(6*H*(*00/@$

>%085J0#(A/%&?1(F$(*($%A<0*$$(5$(5&3#+58#?(G+/>(/&#($%J#+<0*$$(*&?(5>J0#>#&8$(G+/>(>%085J0#(5&8#+G*<#$-($*>#

+%0#(*JJ05#$1

* <T extendsextends superclass>

//this class only accepts type parameters as any class which extends superclass or superclass itself. It means

that if any other type is passing

//it will cause compile time error.

JAVA

classclass Company<T>

{

privateprivate String name;

privateprivate ArrayList<T> eList = newnew ArrayList<>();

publicpublic Company(String name)

{

thisthis.name = name;

}

publicpublic String getName()

{

returnreturn name;

}

publicpublic booleanboolean addEmployee(T employee)

{

ifif(eList.contains(employee))

{

System.out.println((((Employee)employee).getName() + " is already confirmed as an employee of " +

thisthis.name));

returnreturn falsefalse;

}

elseelse {

eList.add(employee);

System.out.println((((Employee)employee).getName() + " is an employee of " + thisthis.name));

returnreturn truetrue;

}

classclass Company<T extendsextends Employee>

{

//(1)

privateprivate String name;

JAVA

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6.7. Raw Types and Backward Compatibility

rF('#&#+5<(<0*$$(/+(5&8#+G*<#(%$#?(@583/%8($J#<5G"5&'(*(</&<+#8#(8"J#-(<*00#?(*(+*@(8"J#1(;35$(+*@(8"J#(#&*A0#$

A*<,@*+?(</>J*85A5058"(@583(#*+05#+(H#+$5/&(/G(D*H*(OA#G/+#(62_(C1LRr(ON5*&'-(ETC[R(The raw types should be used

for backward compatibility(*&?(#05>5&*8#(*00(83#(A#&#G58$(/G(%$5&'(*('#&#+5<(<0*$$1(`*$5<*00"(+*@(8"J#$(A#3*H#$

#c*<80"(05,#(83#"(@#+#(A#G/+#('#&#+5<$1(./(@3#&(@#(%$(F++*"N5$8(@583/%8('#&#+5<(8"J#(*&?(@583(+*@(8"J#(O$##

#c*>J0#(CR-(</?#(+%&$(D%$8(G5&#(*&?(58(5$(0#'*0(*8(</>J50#Q85>#1(;35$(5$(83#(?+*@A*<,(?5$<%$$#?(5&(83#(>/85H*85/&$

*&?(A#&#G58$(5&(M1K(5&(835$(<3*J8#+1

#c*>J0#(C1

#c*>J0#(E1

privateprivate ArrayList<T> eList = newnew ArrayList<>();

publicpublic Company(String name)

{

thisthis.name = name;

}

publicpublic String getName()

{

returnreturn name;

}

publicpublic booleanboolean addEmployee(T employee)

{

ifif(eList.contains(employee))

{

System.out.println(employee.getName() + " is already confirmed as an employee of " + thisthis.name);

returnreturn falsefalse;

}

elseelse

{

eList.add(employee);

System.out.println(employee.getName() + " is an employee of " + thisthis.name);

returnreturn truetrue;

}

ArrayList list = newnew ArrayList();

//raw type -- equivalent to -- ArrayList<Object> list = new ArrayList<Object>

();

JAVA

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6.8. Wildcard Generic Types

r9/%(<*&(%$#(%&A/%&?#?(@50?<*+?$-(A/%&?#?(@50?<*+?$-(/+(0/@#+(A/%&?(@50?<*+?$(8/($J#<5G"(*(+*&'#(G/+(*('#&#+5<

8"J#1rON5*&'-(ETC[R(;3#$#(*+#(%$#G%0(5&(<#+8*5&(<*$#$(A%8(&/8(%$#?(*$(/G8#&(*$(A/%&?#?('#&#+5<(8"J#$1

;3#(G5+$8(8"J#(/G(@50?<*+?(5$(<*00#?(83#(unbounded wildcard(8"J#1(=8(5$($J#<5G5#?(%$5&'(83#(@50?<*+?(<3*+*<8#+(G/+>

?(*&?(*'*5&(58(5$(<*00#?(83#(unbounded wildcard

O388J$BPP?/<$1/+*<0#1</>PD*H*$#P8%8/+5*0PD*H*P'#&#+5<$P%&A/%&?#?450?<*+?$138>0R1(?(5$(83#($*>#(*$(? extends Object(O#1'1(N5$8x\

yR1(Z&A/%&?#?(8"J#(5$(%$#G%0(@3#&(*(>#83/?(?/#$(&/8($J#<5G"(@583(83#(*<8%*0(8"J#(/G(83#(J*+*>#8#+(8*,5&'1(V/+

#c*>J0#-(@3#&("/%(5&H/,#(*(>#83/?(@583(%&A/%&?#?(8"J#-(58(>#*&$(83*8(83#(>#83/?(@500(8*,#($/>#($J#<5G5<(8"J#

A%8(58(?/#$(&/8(,&/@(8500("/%(*??($J#<5G5<(8"J#1(V+/>(83#(G/00/@5&'(#c*>J0#-(J+5&8N5$8OR(>#83/?(8*,#$(05$8(@583

%&$J#<5G5#?(8"J#(*&?(58(5$(*(05$8(/G(%&A/%&?#?P&/&Q$J#<5G5<(8"J#(J*$$#?(*$(*(J*+*>#8#+(8/(*(>#83/?(83*8(8*,#$(*(05$8

/G(%&A/%&?#?(8"J#1

Container<T> is a generic Container classclass

public classclass Container<T>

{

publicpublic voidvoid set(T t){

// }

}

To create a parameterized type of *_Container<T>_*, you must provide a concrete type argument forfor the generic

type parameter T as below.

Container<Double> doubleContainer = newnew Container<>();

If the concrete type is omitted, you will create a raw type of Container<T> and it is

Container rawContainer = newnew Container();

*Using raw types are not safe, you should avoid using raw types.*

JAVA

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Page 122 of 185http://itec2150.gitlab.io/

;3#($#</&?(8"J#(/G(@50?<*+?(5$(<*00#?((upper)bounded wildcard

O388J$BPP?/<$1/+*<0#1</>PD*H*$#P8%8/+5*0PD*H*P'#&#+5<$P%JJ#+`/%&?#?138>0R(*&?(58(5$($J#<5G5#?(@+585&'(r\(#c8#&?$(;r(O#1'1(x\

#c8#&?$(V//y(R1(43#&("/%(%$#(%JJ#+QA/%&?-(*+'%>#&8(<*&(A#(*&"(8"J#(/+($%A<0*$$(/G(8"J#1

;3#(835+?(8"J#(/G(@50?<*+?(5$(lower bounded wildcard

O388J$BPP?/<$1/+*<0#1</>PD*H*$#P8%8/+5*0PD*H*P'#&#+5<$P0/@#+`/%&?#?138>0R(*&?(58(5$($J#<5G5#?(@+585&'(r\($%J#+(;r(O#1'1(x\($%J#+

=&8#'#+yR

publicpublic classclass UnboundedDemo

{

publicpublic voidvoid printList(List<?> list)

{

forfor(Object e: list)

{

System.out.println(e);

}

publicpublic staticstatic voidvoid main(String[] ags)

{

ArrayList<Integer> list1 = newnew ArrayList<>();

list1.add(45);

list1.add(5);

list1.add(105);

printList(list1);

ArrayList<String> list2 = newnew ArrayList<>();

list2.add("Banana");

list2.add("Orange");

list2.add("Apple");

printList(list2);

}

JAVA

Source: https:

//tudip.com/blog-post/java-generics-lower-upper-bound/

publicpublic staticstatic voidvoid validateStringTypes(Collection<? extendsextends String> collection){

//Wild card with Upper bound

// Accept collection of objects of type string or SUB-CLASS of String

}

JAVA

Source: https:

//tudip.com/blog-post/java-generics-lower-upper-bound/

publicpublic staticstatic voidvoid validateTillStringType(Collection<? supersuper String> collection){

//Wild card with Lower bound

// Accept collection of objects of type string or SUPER-CLASS of String

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 123 of 185http://itec2150.gitlab.io/

6.9. Erasure (https://docs.oracle.com/javase/tutorial/java/generics/erasure.html)

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A"(2*&5#0(N5*&'1

q#&#+5<$(@#+#(5&8+/?%<#?(8/(83#(6*H*(0*&'%*'#(8/(J+/H5?#(85'38#+(8"J#(<3#<,$(*8(</>J50#(85>#(*&?(8/($%JJ/+8

'#&#+5<(J+/'+*>>5&'1(;/(5>J0#>#&8('#&#+5<$-(83#(6*H*(</>J50#+(*JJ05#$(8"J#(#+*$%+#(8/B

l#J0*<#(*00(8"J#(J*+*>#8#+$(5&('#&#+5<(8"J#$(@583(83#5+(A/%&?$(/+(UAD#<8(5G(83#(8"J#(J*+*>#8#+$(*+#(%&A/%&?#?1

;3#(J+/?%<#?(A"8#</?#-(83#+#G/+#-(</&8*5&$(/&0"(/+?5&*+"(<0*$$#$-(5&8#+G*<#$-(*&?(>#83/?$1

=&$#+8(8"J#(<*$8$(5G(&#<#$$*+"(8/(J+#$#+H#(8"J#($*G#8"1

q#&#+*8#(A+5?'#(>#83/?$(8/(J+#$#+H#(J/0">/+J35$>(5&(#c8#&?#?('#&#+5<(8"J#$1

;"J#(#+*$%+#(#&$%+#$(83*8(&/(&#@(<0*$$#$(*+#(<+#*8#?(G/+(J*+*>#8#+5a#?(8"J#$e(</&$#d%#&80"-('#&#+5<$(5&<%+(&/

+%&85>#(/H#+3#*?1

6.9.1. Class Type Erasure

2%+5&'(83#(8"J#(#+*$%+#(J+/<#$$-(83#(6*H*(</>J50#+(#+*$#$(*00(8"J#(J*+*>#8#+$(*&?(+#J0*<#(*00(8"J#(J*+*>#8#+$(5&

'#&#+5<(8"J#$(@583(83#5+(A/%&?$(/+(UAD#<8(5G(83#(8"J#(J*+*>#8#+$(*+#(%&A/%&?#?1(;3#(J+/?%<#?(A"8#</?#-

83#+#G/+#-(</&8*5&$(/&0"(/+?5&*+"(<0*$$#$-(5&8#+G*<#$-(*&?(>#83/?$1=&$#+8(8"J#(<*$8$(5G(&#<#$$*+"(8/(J+#$#+H#(8"J#

* complete example.

importimport java.util.ArrayListjava.util.ArrayList;

importimport java.util.Collectionjava.util.Collection;

publicpublic classclass GenericsDemo {

publicpublic staticstatic voidvoid validateTillStringType(Collection<? supersuper String> collection){

//Wild card with Lower bound

// Accept collection of objects of type string or SUPER-CLASS of String

}

publicpublic staticstatic voidvoid validateStringTypes(Collection<? extendsextends String> collection){

//Wild card with Upper bound

// Accept collection of objects of type string or SUB-CLASS of String

}

publicpublic staticstatic voidvoid main(String [] args){

GenericsDemo.validateTillStringType(newnew ArrayList<Object>());

//OK

// GenericsDemo.validateTillStringType(new ArrayList<Integer>());//Error

// GenericsDemo.validateStringTypes(new ArrayList<Object>());//Error

GenericsDemo.validateStringTypes(newnew ArrayList<String>());

//OK

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 124 of 185http://itec2150.gitlab.io/

$*G#8"1(q#&#+*8#(A+5?'#(>#83/?$(8/(J+#$#+H#(J/0">/+J35$>(5&(#c8#&?#?('#&#+5<(8"J#$1;"J#(#+*$%+#(#&$%+#$(83*8

&/(&#@(<0*$$#$(*+#(<+#*8#?(G/+(J*+*>#8#+5a#?(8"J#$e(</&$#d%#&80"-('#&#+5<$(5&<%+(&/(+%&85>#(/H#+3#*?1r

6.9.2. Erasure of Generic Methods

43#&(83#(</>J50#+(8+*&$0*8#$('#&#+5<(>#83/?(J+5&8(5&8/(A"8#</?#$-(58(+#>/H#$(83#(8"J#QJ*+*>#8#+(*&?(+#J0*<#(83#

8"J#(J*+*>#8#+(@583(*<8%*0(8"J#1(;35$(J+/<#$$(5$(,&/@&(*$(#+*$%+#1

Source: https:

//www.baeldung.com/java-type-erasure[Baeldung]

publicpublic staticstatic <E> booleanboolean containsElement(E [] elements, E element)

{

forfor (E e : elements)

{

ifif(e.equals(element))

{

returnreturn truetrue;

}

returnreturn falsefalse;

}

After the compilation, the the compiler replaces the unbound type parameter E with Object.

publicpublic classclass Stack

{

privateprivate Object[] stackContent;

publicpublic Stack(intint capacity)

{

thisthis.stackContent = (Object[]) newnew Object[capacity];

}

publicpublic voidvoid push(Object data)

{

// ..

}

publicpublic Object pop()

{

// ..

}

JAVA

print method with type parameter.

publicpublic staticstatic <E> voidvoid print(E[] arr)

{

forfor (E element : arr)

{

System.out.printf("%s ", element);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

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6.10. Key Terms

A/%&?#?(8"J#B(F('#&#+5<(8"J#(A#5&'($J#<5G5#?(*$(*($%A8"J#(/G(*&/83#+(8"J#

%JJ#+(A/%&?#?(@50?<*+?(Ox\(#c8#&?$(byRB(A/%&?$(@583(%JJ#+(5&3#+58*&<#(</&$8+*5&8(A"(%$5&'(#8#&?$(,#"@/+?1

0/@#+(A/%&?(@50?<*+?(Ox\($%J#+(byRB(A/%&?$(5$(%$5&'(83#(@50?<*+?(<3*+*<8#+(O\R-(G/00/@5&'(A"(83#($%J#+(,#"@/+?(A"

58$(0/@#+(A/%&?1

%&A/%&?#?(@50?<*+?Ox\yRB(A/%&?$(@35<3(5$($J#<5G5#?(%$5&'(x\y1(835$(5$(<*00#?(%&,&/@&(8"J#1

+*@(8"J#B(*(&*>#(/G(*('#&#+5<(<0*$$(/+(5&8#+G*<#(@583/%8(*&"(8"J#(*+'%>#&8$1

8"J#(#+*$%+#B(83#(J+/<#$$(/G(8"J#(<3#<,5&'(/&0"(*8(</>J50#(85>#(*&?(?5$<*+?5&'(83#(#0#>#&8(8"J#(5&G/+>*85/&(*8

+%&85>#1

6.11. Exercises

6.11.1. Exercise 1 (Palindrome)

4+58#(*('#&#+5<(>#83/?(8/(</%&8(83#(&%>A#+(/G(J*05&?+/>#$(5&(*(</00#<85/&1(.8#J(CB(Z$#(*('#&#+5<(=;#$8#+(5&8#+G*<#

@583(*(>#83/?(&*>#(test(?#G5&#?(*$(G/00/@$B

J%A05<(5&8#+G*<#(=;#$8#+x;y(z(J%A05<(A//0#*&(8#$8O;(/ADRe(}

.8#J(EB(4+58#()*05&?+/>#(<0*$$(*&?(835$(<0*$$(5>J0#>#&8$('#&#+5<(=;#$8#+(5&8#+G*<#(*&?(?#G5&#(83#(8#$8(>#83/?(8/

8#$8(5G(83#(H*0%#(5$(*(J*05&?+/>#(/+(&/81

)*05&?+/># O388J$BPP@@@1>#++5*>Q@#A$8#+1</>P?5<85/&*+"PJ*05&?+/>#R(5$(*(@/+?-(H#+$#-(/+($#8#&<#(/+(*(&%>A#+(83*8(+#*?$

83#($*>#(A*<,@*+?(/+(G/+@*+?(O$%<3(*$(rl*<#(<*+r-rS*?*>(=m>(F?*>1r-rC[[Cr-rF>/+#-(l/>*r-r_5&'-(*+#("/%('0*?

"/%(*+#(,5&'\r(.8#J(IB(4+58#(*(7/%&8#+(<0*$$(*&?(?#G5&#(*('#&#+5<(>#83/?(&*>#?(countIf1(;35$(>#83/?(@500(</%&8

83#(&%>A#+(/G(#0#>#&8$(5&(*(</00#<85/&(83*8(3*H#(J*05&?+/>#$(*&?(*0$/(@500(5'&/+#(&/&Q*0J3*(<3*+*<8#+$(*&?(@358#

$J*<#$1

6.11.2. Exercise 2

4+58#(*('#&#+5<(>#83/?(8/($@*J(83#(J/$585/&$(/G(8@/(?5GG#+#&8(#0#>#&8$(5&(*&(*++*"1

By defaultdefault all generic types are replaced with type Object as you see follows.

Upon compilation, the compiler replaces the type paramter E with Object.

publicpublic staticstatic voidvoid print(Object[] arr)

{

forfor (Object element : arr)

{

System.out.printf("%s ", element);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 126 of 185http://itec2150.gitlab.io/

6.11.3. Exercise 3

4+58#(*('#&#+5<(>#83/?(83*8(?5$J0*"$(*++*"(#0#>#&8

6.11.4. Exercise 4

4+58#(*('#&#+5<(>#83/?($#0#<85/&./+8(A*$#?(/&(83#($#0#<85/&./+8(>#83/?(*$(G/00/@$1(Z$#(83#('#&#+5<($@*J(>#83/?

G+/>(83#(bc#+<5$#(E1(Z$#(x;(#c8#&?$(7/>J*+*A0#x;yy(5&(83#(8"J#QJ*+*>#8#+($#<85/&(G/+(835$(>#83/?1(S*,#($%+#(%$#

</>J*+#;/(8/(</>J*+#(83#(/AD#<8$(/G(83#(8"J#(83*8(;(+#J+#$#&8$1

6.11.5. Exercise 5

4+58#(*(8#$8(J+/'+*>(83*8(5&J%8$-($/+8$-(*&?(/%8J%8$(*&(2/%A0#(*++*"(*&?(=&8#'#+(*++*"1(Z$#(83#('#&#+5<($@*J

>#83/?-('#&#+5<(?5$J0*"F++*"(>#83/?-(*&?('#&#+5<($#0#<85/&./+8(>#83/?1

!#+#(5$(83#($*>J0#(+%&B

6.12. References

`*#0?%&'1OETETR1(;3#(`*$85<$(/G(6*H*(q#&#+5<$1(l#8+5#H#?(G+/>(388J$BPP@@@1A*#0?%&'1</>PD*H*Q'#&#+5<$(6%&#*%-(61

OETCKR1(Generics: _How They Work and Why They Are Important-(l#8+5#H#?(388J$BPP@@@1/+*<0#1</>P8#<3&5<*0Q

+#$/%+<#$P*+85<0#$PD*H*PD%&#*%Q'#&#+5<$138>01

N5*&'-(21(OETC[R1(Introduction to Java: Programming and Data Structures(OCC83(#?1R1()#*+$/&

6.13. Issue Tracker/Comments

=$$%#(;+*<,#+ O388J$BPP'583%A1</>P3J*+,WP3#0JY?#$,P5$$%#$R

publicpublic staticstatic voidvoid selectionSort(doubledouble[] list)

{

forfor (intint i = 0; i < list.length - 1; i++)

{

intint smallest = i;

forfor (intint index = i + 1; index < list.length; index++)

ifif (list[index] < list[smallest])

smallest = index;

swap(list, i, smallest);

// swap smallest element into position

}

JAVA

Original Double array elements

[2.3, 45.6, 4.5, 11.6, 2.0]

Double array elements after the selection sort

[2.0, 2.3, 4.5, 11.6, 45.6]

Original Integer array elements

[3, 56, 1, 12, 7, 90, 45, 23]

Double array elements after the selection sort

[1, 3, 7, 12, 23, 45, 56, 90]

4/5/21, 10)50 PMIntermediate Programming

Page 127 of 185http://itec2150.gitlab.io/

7. Recursion

7.1. Learning Outcomes

Z&?#+$8*&?(83#(A*$5<$(/G(+#<%+$5/&

N#*+&(@3"(+#<%+$5/&(<*&(A#(%$#G%0

N#*+&(3/@(8/(*JJ0"(+#<%+$5/&(8/($/0H#($5>J0#(J+/A0#>$

N#*+&(@3"("/%($3/%0?(&/8(%$#(+#<%+$5/&(G/+(G5A/&*<<5(&%>A#+$(*&?(G*<8/+5*0$

7.2. Resources

7.2.1. Text and Tutorials

=&8+/?%<85/&(8/()+/'+*>>5&'(Z$5&'(6*H*Q(b5'383(b?585/&(A"(2*H5?(61(b<,B(73*J8#+(^

O388JBPP>*8313@$1#?%PD*H*&/8#$P<^P$C138>0R(73*J8#+(^(Q(N5&,#?(2*8*(.8+%<8%+#$(*&?(l#<%+$5/&

6*H*-(6*H*-(6*H*B(UAD#<8QU+5#&8#?()+/A0#>(./0H5&'(A"(l*0J3(S/+#005(*&?(l*0J3(4*0?#B

388JBPP@@@1<$18+5&</001#?%Pt+*>PDDDPDDDQ/$QETCWTMEL1J?G(73*J8#+(CE(l#<%+$5H#()+/A0#>(./0H5&'

7.2.2. Videos

6*H*(l#<%+$5/&(B(388J$BPP@@@1"/%8%A#1</>P@*8<3\H]&#%2%GY5[.'

F0'/+583>(l#<%+$5/&(B(388J$BPP@@@1"/%8%A#1</>P@*8<3\H]_bb_&WS#Q>$

7.3. Introduction

l#<%+$5/&(5$(*&(*<85/&(83*8(?#$<+5A#$(*(>#83/?(<*005&'(58$#0G1(;3#(G/00/@5&'(5$(*&($5>J0#(#c*>J0#(/G(+#<%+$5/&

@35<3(<*0<%0*8#$(83#(&Q83(G5A/&*<<5(&%>A#+

;3#(G5A/&&*<<5($#d%#&<#(?#G5&#$(*($#d%#&<#(/G(&%>A#+$(@3#+#(83#(&Q83(&%>A#+(5$(83#(*??585/&(/G(83#(O&QCR(83(*&?

O&QER(83(&%>A#+1(j/85<#(83*8(835$(+#<%+$5H#($/0%85/&(8/(<*0<%0*85&'(83#(G5A/&*<<5(&%>A#+(5$(H#+"($0/@1(=&(G*<8-(58(5$

>%<3($0/@#+(83*&(83#(58#+*85H#(O%$5&'(0//J$R(H#+$5/&1

;3#(+#*$/&(G/+(835$(5$(A#<*%$#(83#($*>#(>#83/?(<*00('#8$(<*00#?(/H#+(*&?(/H#+(*'*5&1(V/+(#c*>J0#-(<*0<%0*85&'(83#

L83(G5A/&&*<<5(&%>A#+(@/%0?(8*,#(Ln(<*00$(8/('#8V5AOR1

publicpublic intint getFib(intint num)

{

ifif(num == 1 || num == 2)

{

returnreturn 1;

}

elseelse

{

returnreturn getFib(num - 1) + getFib(num + 2);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 128 of 185http://itec2150.gitlab.io/

./0H5&'(J+/A0#>$(+#<%+$5H#0"(>*"(&/8(*0@*"$(+#$%08(5&(83#(>/$8(#GG5<5#&8($/0%85/&(A%8(83#(+#*$/&(+#<%+$5/&(5$

%$#G%0(5$(A#<*%$#(+#<%+$5/&(<*&(0#*?(8/($/0%85/&$(83*8(*+#(#*$"(8/(%&?#+$8*&?(*&?(5>J0#>#&81(O;35$(@500(A#

*JJ*+#&8(5&(8+*H#+$*0$(5&(A5&*+"(8+##$R

43#&($/0H5&'(J+/'+*>>5&'(+#<%+$5H#0"-("/%(>%$8(835&,(/G(83#(A*$#(<*$#(*&?(83#(+#<%+$5H#(<*$#1

Base caseB(83#($5>J0#$8(<*$#(8/(</&$5?#+

Recursive caseB(<*005&'(83#(+#<%+$5/&(>#83/?(@583(*($5>J05G5#?(O/+($>*00#+R(H*0%#

V/+(#c*>J0#-(</&$5?#+(83#(J+/A0#>(/G(G5&?5&'(83#(+#H#+$#(/G(*($8+5&'1

j/85<#(83*8(83#(A*$#(<*$#(3*&?0#$(@3#&(83#(0#&'83(/G(83#($8+5&'(5$(a#+/1(UG(</%+$#-(@3#&(83#(0#&'83(/G(83#($8+5&'(5$

a#+/-(83#(#>J8"($8+5&'(5$(+#8%+&#?1(=&(83#(+#<%+$5H#(<*$#-(83#($*>#(>#83/?(5$(<*00#?(*'*5&(@583(*(H*0%#(83*8(5$

r<0/$#+r(8/(83#(A*$#(<*$#1

!#+#(5$(*&/83#+(#c*>J0#(@3#+#(%$5&'(+#<%+$5/&(+#$%08$(5&(*($5>J0#+($/0%85/&(83*&(83#(58#+*85H#(H#+$5/&1(;3#

J+/A0#>(5$(J+5&85&'(*00(A5&*+"(&%>A#+$(@583(&Q?5'58$1

;3#(58#+*85H#(H#+$5/&(/G(J+5&85&'(*00(A5&*+"(&%>A#+$(5$(*(A58(>/+#(</>J05<*8#?(*&?(5&H/0H#$(%$5&'(*(N5$81

publicpublic String getReverseString(String str)

{

ifif (str.length() == 0)

{

returnreturn "";

}

elseelse

{

returnreturn str.substring(str.length()-1) + getReverseString(str.substring(0,str.length()-1));

}

JAVA

publicpublic staticstatic voidvoid printBinaryNumber(String str, intint length)

{

ifif (length == 0)

{

System.out.println(str);

returnreturn;

}

printBinaryNumber(str + "0", length - 1);

printBinaryNumber(str + "1", length - 1);

}

JAVA

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;35$(500%$8+*8#$(83*8(+#<%+$5/&(<*&(0#*?(8/($/0%85/&$(83*8(*+#(#*$5#+(8/(%&?#+$8*&?1(4583(*(A58(/G(<+#*85H58"("/%(<*&

@+58#(#H#+"(58#+*85H#($/0%85/&(8/(*(+#<%+$5H#(/&#(*&?(H5<#QH#+$*1()0#*$#(@*8<3(83#(G/00/@5&'(H5?#/(*$(*(+#H5#@(/G(83#

A*$5<(</&<#J8$(/G(+#<%+$5/&B

Algorithms: Recursion

7.4. Permutations and Combinations

publicpublic staticstatic voidvoid printBinaryNumberIterative(intint length)

{

ArrayList<String> list = newnew ArrayList<String>();

list.add("0");

list.add("1");

intint max = (intint) Math.pow(2, length);

whilewhile (list.size() < max)

{

String temp = list.remove(0);

list.add(temp + "0");

list.add(temp + "1");

}

System.out.println(list);

}

JAVA

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F(G*>/%$(*JJ05<*85/&(/G(+#<%+$5/&(5$(G/%&?(5&('#&#+*85&'(J#+>%8*85/&$1(V/+(#c*>J0#-('#&#+*85&'(*00(83#

J#+>%8*85/&$(/G(83#(@/+?(r<*+r(+#$%08$(5&(r<*+r-(r<+*r-(r*<+r-(r*+<r-(r+<*r-(*&?(r+*<r1(j/85<#(83*8(5G(83#+#(*+#(&Q

<3*+*<8#+$(5&(*(@/+?-(58(@500(+#$%08(5&(&n(J#+>%8*85/&$1(;3#(G/00/@5&'(5>*'#(500%$8+*8#$(3/@(*&(+#<%+$5/&('#&#+*8#$

83#(J#+>%8*85/&$1

!#+#(5$(*&(#c*>J0#(/G('#&#+*85&'(83#(</>A5&*85/&$(/G(*($8+5&'1(;35$(+#<%+$5H#($/0%85/&$(%$#$(*(3#0J#+(>#83/?1

publicpublic staticstatic ArrayList<String> permutations(String str)

{

ArrayList<String> result = newnew ArrayList<>();

ifif (str.length() == 1)

{

result.add(str);

returnreturn result;

}

forfor (intint i = 0; i < str.length(); i++)

{

String part = str.substring(0, i) + str.substring(i + 1);

ArrayList<String> permutes = permutations(part);

forfor (String s : permutes)

{

result.add(str.charAt(i) + s);

}

returnreturn result;

}

JAVA

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7.5. Using Recursion in Mazes

publicpublic staticstatic ArrayList<String> combinations(String str)

{

ArrayList<String> combos = newnew ArrayList<String>();

forfor (intint i = 1; i <= str.length(); i++)

{

combinations(i, str, combos);

}

returnreturn combos;

}

publicpublic staticstatic ArrayList<String> combinations(intint length, String str, ArrayList<String> combos)

{

ifif (str.length() == length)

{

ifif (!combos.contains(str))

{

combos.add(str);

}

elseelse

{

forfor (intint i = 0; i < str.length(); i++)

{

String shortened = str.substring(0, i) + str.substring(i + 1);

combos = combinations(length, shortened, combos);

}

returnreturn combos;

}

JAVA

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Page 132 of 185http://itec2150.gitlab.io/

F&(5&8#+#$85&'(J+/A0#>(83*8(<*&(A#($/0H#?(@583(+#<%+$5/&(*+#(>*a#$1(S*a#$(<*&(A#($/0H#?(H#+"(&*8%+*00"(@583

+#<%+$5/&(*$(J0*"(58$#0G(>*J$(8/(+#<%+$5/&(H#+"(@#001(;3#(5?#*(5$(8/(8+"(/%8(*00(J*83$(*&?($#0#<8(83#(J*83(83*8(0#*?$(8/

83#(#c581(;3#(G/00/@5&'(</?#(500%$8+*8#$(3/@(+#<%+$5/&(<*&(A#(%$#?(8/(G5&?(83#($/0%85/&(8/(*(>*a#1

7.6. Summary

S*,#($%+#("/%(3*H#(*(A*$#(<*$#(*&?(<3#<,$(8/(*H/5?(5&G5&58#(+#<%+$5/&

Z&?#+$8*&?(83*8("/%(<*&(+#@+58#(*&"(+#<%+$5H#(>#83/?(58#+*85H#0"(*&?(H5<#QH#+$*

`#(*A0#(8/($/0H#($5>J0#(J+/A0#>$(%$5&'(+#<%+$5/&

7.7. Key Terms

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7.8. Exercises

C1( 4+58#(*(+#<%+$5H#(>#83/?(83*8(+#H#+$#$(*($8+5&'1(V/+(#c*>J0#-("/%+(>#83/?($3/%0?(J+5&8(/%8(r+*<r('5H#&(83#

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publicpublic booleanboolean findPath(Maze maze, Point position)

JAVA

4/5/21, 10)50 PMIntermediate Programming

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7.9. Issue Tracker/Comments

=$$%#(;+*<,#+ O388J$BPP'583%A1</>P3J*+,WP3#0JY?#$,P5$$%#$R

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8. Basic Data Structures and Sorting

8.1. Learning Objectives

.8%?#&8$(@500(A#(*A0#(8/B

2#G5&#(*&?(?#$<+5A#(G/%+(A*$5<(*A$8+*<8(?*8*($8+%<8%+#$B(N5$8-(.8*<,-(p%#%#(*&?()+5/+58"(p%#%#1

FJJ0"(83#(A*$5<(*A$8+*<8(?*8*($8+%<8%+#$(8/(?#H5$#(#GG5<5#&8(*0'/+583>$(G/+($/0H5&'(</>J%8*85/&*0(J+/A0#>$1

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FJJ0"(F++*"$1$/+8-(F++*"$1$/+8(*&?(7/00#<85/&$1$/+8(8/(J+/H5?#(#GG5<5#&8($/0%85/&$(8/(J+/A0#>$(@3#+#($/+85&'(5$

A#&#G5<5*01

8.2. Resources

8.2.1. Text

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;3#(S=;()+#$$1

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8.3. Introduction

=&(J+/'+*>>5&'-(*(?*8*($8+%<8%+#(5$(*(>#*&$(8/(/+'*&5a#(*(</00#<85/&(/G(?*8*1(F(?*8*($8+%<8%+#(&/8(/&0"($8/+#$(83#

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+#J+#$#&8#?(*&?(/+'*&5a#?(5$(<+%<5*0(G/+(83#(</++#<8&#$$(*&?(#GG5<5#&<"(/G(83#(J+/'+*>1

;3#(G5+$8(?*8*($8+%<8%+#("/%(3*H#(0#*+&#?-(*&?(J#+3*J$(83#($5>J0#$8(/G(*00(?*8*($8+%<8%+#$-(5$(*&(array1(F&(*++*"(5$(*

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H#+"(</>>/&0"(%$#?-(?%#(8/(58$($5>J05<58"(*&?(83#(#GG5<5#&<"(5&(*<<#$$5&'(*&"(#0#>#&8(/G(83#(*++*"1(!/@#H#+-(*

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*??(*(&#@(#0#>#&8(8/(83#(*++*"(/+(+#>/H#(*&(#c5$85&'(#0#>#&8(G+/>(83#(*++*"1(V/+(83#(>*&"(*JJ05<*85/&$(@3#+#

83#(?*8*(&##?$(8/('+/@(O*&?($3+5&,R(?"&*>5<*00"-(@#(?#$5+#(*(dynamic(?*8*($8+%<8%+#(83*8($%JJ/+8$(#GG5<5#&8

/J#+*85/&$(G/+(5&$#+85/&(*&?(?#0#85/&-(*>/&'(/83#+(5>J/+8*&8(/J#+*85/&$1

=&(835$(<3*J8#+-(@#(5&8+/?%<#(G/%+(A*$5<(?"&*>5<(?*8*($8+%<8%+#$B(05$8$-($8*<,$-(d%#%#$(*&?(J+5/+58"(d%#%#$1(;3#

G/<%$(3#+#(5$(8/(?#G5&#(83#>(*&?(?#$<+5A#(83#5+(%$*'#1(=&(=;b7(ICLTB(F?H*&<#?()+/'+*>>5&'-("/%(@500(0#*+&(83#5+

5>J0#>#&8*85/&$(*$(@#00(*$(83#5+(#GG5<5#&<"1

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8.4. Lists

F,5&(8/(*&(*++*"-(*(05$8(5$(*(sequentially ordered(</00#<85/&(/G(OJ/$$5A0"(?%J05<*8#R(/AD#<8$1(F(G%&?*>#&8*0(?5GG#+#&<#

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+#>/H#(#c5$85&'(#0#>#&8$(G+/>(*(05$8-(@3#+#*$(*&(*++*"(5$($8*85<1(S/+#/H#+-(*?D*<#&8(#0#>#&8$(5&(*(05$8(>*"(not

+#$5?#(5&(</&85'%/%$(0/<*85/&$(5&(83#(>#>/+"-(*$(5&(83#(<*$#(/G(*(linked list(83*8(5$(?5$<%$$#?(A#0/@1

8.4.1. The Java List Interface

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`#0/@(@#($%>>*+5a#($/>#(</>>/&0"(%$#?(>#83/?$(5&(83#(5&8#+G*<#(ListxEy-(@3#+#(E(5$(83#('#&#+5<(8"J#(/G(83#

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A//0#*&(addOE(#R1(F??$(83#($J#<5G5#?(#0#>#&8(8/(83#(end(/G(83#(05$8-(*&?(+#8%+&$(true(5G(83#(#0#>#&8(5$

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;3#(>#83/?(83+/@$(*(NullPointerException(5G(83#($J#<5G5#?(</00#<85/&(5$(null1

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IndexOutOfBoundException(5G(83#($J#<5G5#?(5&?#c(5$(/%8(/G(+*&'#-(51#1(5G(O5&?#c(x(T(~~(5&?#c(y($5a#ORR1

E(removeO5&8(5&?#cR1(l#>/H#$(*&?(+#8%+&$(83#(#0#>#&8(*8(83#($J#<5G5#?(5&?#c(G+/>(83#(05$81(;3#(>#83/?(83+/@$

*&(IndexOutOfBoundException(5G(83#($J#<5G5#?(5&?#c(5$(/%8(/G(+*&'#-(51#1(5G(O5&?#c(x(T(~~(5&?#c(y]($5a#ORR1

j/85<#(83#($05'38(?5GG#+#&<#(5&(83#(/%8Q/GQ+*&'#(</&?585/&(A#8@##&(add(*&?(remove1

A//0#*&(removeOObject(/R1(l#>/H#$(83#(G5+$8(/<<%++#&<#(/G(83#($J#<5G5#?(/AD#<8(G+/>(83#(05$8-(5G(83#(/AD#<8

#c5$8$1(;3#(>#83/?(+#8%+&$(true(5G(83#($J#<5G5#?(/AD#<8(5$(J+#$#&8(5&(83#(05$8-(*&?(false(/83#+@5$#1

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IndexOutOfBoundException(5G(83#($J#<5G5#?(5&?#c(5$(/%8(/G(+*&'#-(51#1(5G(O5&?#c(x(T(~~(5&?#c(y]($5a#ORR1

E(setO5&8(5&?#c-(E(#R1(l#J0*<#$(83#(#0#>#&8(*8(83#($J#<5G5#?(5&?#c(@583(83#($J#<5G5#?(#0#>#&8-(*&?(+#8%+&$(83#

#0#>#&8(J+#H5/%$0"($8/+#?(*8(83#($J#<5G5#?(5&?#c1(;3#(>#83/?(83+/@$(*&(IndexOutOfBoundException(5G(83#

$J#<5G5#?(5&?#c(5$(/%8(/G(+*&'#-(51#1(5G(O5&?#c(x(T(~~(5&?#c(y]($5a#ORR1

A//0#*&(containsOObject(/R1(l#8%+&$(true(5G(*&?(/&0"(5G(83#(05$8(</&8*5&$(83#($J#<5G5#?(/AD#<81

5&8(indexOfOObject(/R1(l#8%+&$(83#(5&?#c(/G(83#(G5+$8(/<<%++#&<#(/G(83#($J#<5G5#?(/AD#<8(5G(83#(/AD#<8(5$(5&(83#(05$8-

*&?(QC(/83#+@5$#1

5&8(lastIndexOfOObject(/R1(l#8%+&$(83#(5&?#c(/G(83#(0*$8(/<<%++#&<#(/G(83#($J#<5G5#?(/AD#<8(5G(83#(/AD#<8(5$(5&(83#

05$8-(*&?(QC(/83#+@5$#1

5&8(sizeOR1(l#8%+&$(83#($5a#(/G(83#(05$8-(51#1(83#(&%>A#+(/G(#0#>#&8$(5&(83#(05$81

A//0#*&(isEmptyOR1(l#8%+&$(true(5G(*&?(/&0"(5G(83#(05$8(5$(#>J8"-(51#1($5a#OR(]](T1

4/5/21, 10)50 PMIntermediate Programming

Page 136 of 185http://itec2150.gitlab.io/

H/5?(clearOR1(70#*+$(83#(05$81(j/8#(83*8(83#(5>J0#>#&8*85/&(/G(835$(>#83/?(&##?(not(+#>/H#(83#(#0#>#&8$(/G(83#

05$81(F00(58(&##?$(5$(8/(<+#*8#(*(&#@(#>J8"(05$81

A//0#*&(equalsOObject(/R1(l#8%+&$(true(5G(*&?(/&0"(5G(83#($J#<5G5#?(/AD#<8(5$(*(05$8(83*8(</&8*5&$(83#($*>#

#0#>#&8$(5&(83#($*>#(/+?#+(*$(835$(05$81

ListIteratorxEy(listIteratorOR1(l#8%+&$(*(list iterator($8*+85&'(*8(83#(A#'5&&5&'(/G(83#(05$8(83*8(*00/@$(/&#(8/

8+*H#+$#(83#(05$8(5&(A/83(?5+#<85/&$(*&?(>*&5J%0*8#(83#(05$8(#&(+/%8#1(4#(@500(?5$<%$$(83#(N5$8(=8#+*8/+(5&(>/+#

?#8*50$-(5&(83#($%A$#<85/&(?#H/8#?(8/(581

ListIteratorxEy(listIteratorO5&8(5&?#cR1(l#8%+&$(*(05$8(58#+*8/+($8*+85&'(*8(83#($J#<5G5#?(J/$585/&(5&(83#(05$81(;3#

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8.4.2. The ArrayList and LinkedList Classes

ArrayList(*&?(LinkedList(*+#(83#(8@/(<0*$$#$(83*8(5>J0#>#&8(83#(List(5&8#+G*<#1

Array List

9/%(*0+#*?"(0#*+&#?(83#(ArrayList(<0*$$(5&(=;b7(ECKTB()+/'+*>>5&'(V%&?*>#&8*0$ O388JBPP58#<ECKT1'580*A15/PR1(9/%

0#*+&#?(3/@(8/(<+#*8#(*&(ArrayList(/AD#<8(*&?(3/@(8/(>*&5J%0*8#(*&(ArrayList(A"(<*005&'(58$(>#83/?$1(;/(*??(8/

"/%+(,&/@0#?'#-(@#(A+5#G0"(?#$<+5A#(3#+#(3/@(*&(*++*"(05$8(5$(5>J0#>#&8#?1

;3#(ArrayList(<0*$$(5>J0#>#&8$(*(05$8(@583(*(resizable array1(;3*8(5$-(83#(backing data structure(/G(*&(ArrayList(5$

*&(array1(;3#(A*<,5&'(*++*"(5$(*&(5&$8*&<#(H*+5*A0#(/G(*&(ArrayList(/AD#<8(*&?($8/+#$(*00(83#(#0#>#&8$(/G(83#(05$81

;3#+#G/+#(5&8#+&*00"-(*<<#$$5&'(*&(#0#>#&8(/G(83#(*++*"(05$8(A"(5&?#c-(@35<3(5$(+#d%5+#?(G/+(>#83/?$($%<3(*$(getO5&8

5&?#cR(*&?(setO5&8(5&?#c-(E(#R-(5$($5>J0"(*<<#$$5&'(83#(#0#>#&8(5&(83#(A*<,5&'(*++*"(A"(5&?#c1(43#&(*(&#@(#0#>#&8

5$(*??#?(8/(83#(05$8(*&?(83#(A*<,5&'(*++*"(5$(*A/%8(8/(A#(G%00-(83#(add(>#83/?(@/%0?(<+#*8#(*(new larger(*++*"

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@#00(*$(83#(&#@(#0#>#&8(8/(83#(&#@(*++*"-(*&?(>*,#(83#(&#@(*++*"(83#(A*<,5&'(*++*"1(4350#(+#$5a5&'(5$(*&

#cJ#&$5H#(/J#+*85/&-($%<3(*&(#H#&8(/<<%+$(5&G+#d%#&80"1

Linked List

=&(*(linked list-(#H#+"(05$8(#0#>#&8-(%$%*00"(<*00#?(*(node-(3*$(*(?*8*(G5#0?(*&?(>*5&8*5&$(8@/(J/5&8#+$(O51#1

+#G#+#&<#$R(Q(/&#(J/5&85&'(8/(83#(J+#H5/%$(&/?#(*&?(83#(/83#+(J/5&85&'(8/(83#(&#c8(&/?#1(;3#+#(*+#(8@/($J#<5*0

&/?#$(Q(83#(head(@35<3(5$(83#(G5+$8(&/?#(/G(83#(05$8-(*&?(83#(tail(@35<3(5$(83#(0*$8(&/?#(/G(83#(05$81(;3#(&/?#(J+#H5/%$

8/(83#(3#*?(5$(null-($/(5$(83#(&/?#(&#c8(8/(83#(8*501(;3#(G/00/@5&'(G5'%+#(?#J5<8$(*(05&,#?(05$8(/G(5&8#'#+(#0#>#&8$1

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=&(83#(G5'%+#-(#*<3($d%*+#(+#J+#$#&8$(*(&/?#(/G(83#(05$81(;3#(0#G8>/$8(&/?#(5$(83#(3#*?(*&?(83#(+5'38>/$8(/&#(5$(83#

8*501(;3#(&%>A#+(5&$5?#(#*<3(&/?#(+#J+#$#&8$(83#(H*0%#(/G(58$(?*8*-(*&?(83#(&%>A#+(*A/H#(+#J+#$#&8$(58$(5&?#c1(F8

#*<3(&/?#-(83#(*++/@(J/5&85&'(8/(83#(+5'38(+#J+#$#&8$(83#(J/5&8#+(8/(83#(&#c8(&/?#-(*&?(83*8(J/5&85&'(8/(83#(0#G8

+#J+#$#&8$(83#(J/5&8#+(8/(83#(J+#H5/%$(&/?#1(V+/>(#*<3(&/?#(/&#(<*&(?5+#<80"(*<<#$$(A/83(&#5'3A/+$(A"(G/00/@5&'

83#(J/5&8#+$1(;3#(8@/(&#5'3A/+$(*+#(3/@#H#+(83#(only(&/?#$(83*8(*+#(?5+#<80"(*<<#$$5A0#(G+/>(*(&/?#-(A#<*%$#(83#

&/?#$(/G(*(05&,#?(05$8(</%0?(+#$5?#(5&(arbitrary(>#>/+"(0/<*85/&$-(*$(/JJ/$#?(8/(</&85'%/%$(>#>/+"(0/<*85/&$(*$(5&

83#(<*$#(/G(*&(*++*"(05$81(;3#+#G/+#-(*<<#$$5&'(#0#>#&8$(/G(*(05&,#?(05$8(A"(5&?#c-(@35<3(5$(+#d%5+#?(G/+(>#83/?$($%<3

*$(getO5&8(5&?#cR(*&?(setO5&8(5&?#c-(E(#R-(5$(*($0/@(/J#+*85/&-(*$(58(+#d%5+#$(8/(8+*H#+$#(83#(#&85+#(05$8(8/($#*+<3(G/+

83#(&/?#(*8(83#($J#<5G5#?(5&?#c1

=&(J+5&<5J0#-(*(05&,#?(05$8(<*&(A#(+#J+#$#&8#?(A"(#583#+(58$(3#*?(/+(58$(8*50-(A#<*%$#(G+/>(#583#+(#&?(/&#(<*&(8+*H#+$#

83#(#&85+#(05$81(V/+(</&H#&5#&<#(*&?(#GG5<5#&<"(3/@#H#+-(*($8*&?*+?(5>J0#>#&8*85/&-(*$(83#(/&#(G/+(83#(6*H*

LinkedList(<0*$$-(8+*<,$(A/83(83#(3#*?(*&?(83#(8*50(/G(*(05&,#?(05$8(/AD#<8(*$(58$(J+5H*8#(5&$8*&<#(H*+5*A0#$-(*$

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5&8#+G*<#-(83#(LinkedList(<0*$$(J+/H5?#$(83#(G/00/@5&'(>#83/?$(involving just the head or the tail(/G(*

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NoSuchElementException(5G(83#(05$8(5$(#>J8"1

E(removeLastOE(#R1(l#>/H#$(*&?(+#8%+&$(83#(#0#>#&8(*8(83#(tail(/G(05$81(FG8#+(835$(>#83/?-(83#(J+#?#<#$$/+(O5&

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NoSuchElementException(5G(83#(05$8(5$(#>J8"1

E(getFirstOR1(l#8%+&$(83#(?*8*(*8(83#(head(/G(83#(05$81(;3#(>#83/?(83+/@$(*(NoSuchElementException(5G(83#(05$8

5$(#>J8"1

E(getLastOR1(l#8%+&$(83#(?*8*(*8(83#(tail(/G(83#(05$81(;3#(>#83/?(83+/@$(*(NoSuchElementException(5G(83#(05$8(5$

#>J8"1

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;3#(?#G*%08(</&$8+%<8/+(LinkedListOR(<+#*8#$(*&(#>J8"(05&,#?(05$81

4/5/21, 10)50 PMIntermediate Programming

Page 138 of 185http://itec2150.gitlab.io/

;3#(</&$8+%<8/+(LinkedListOCollectionx\(#c8#&?$(Ey(<R(<+#*8#$(*(05&,#?(05$8(83*8(</&8*5&$(83#(#0#>#&8$(/G(83#

$J#<5G5#?(</00#<85/&-(5&(83#($*>#(/+?#+(*$(?#G5&#?(A"(83#(</00#<85/&m$(58#+*8/+1

8.4.3. The List Iterator

;3#(ListIterator(5&8#+G*<#($J#<5G5#$(*&(58#+*8/+(83*8(*00/@$(/&#(8/(8+*H#+$#(*(05$8(5&(A/83(?5+#<85/&$(*&?(>*&5J%0*8#

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>#83/?(83*8(+#d%5+#$(8/($#*+<3(83#(05$81

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ListIteratorxEy(5&8#+G*<#1(`#0/@(@#($%>>*+5a#(58$(>#83/?$1

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hasNextOR(@/%0?(+#8%+&(8+%#R1(U83#+@5$#(83#(>#83/?(83+/@$(*(NoSuchElementException1

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@/%0?(+#8%+&(8+%#Re(/83#+@5$#(+#8%+&$(QC1

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83#(05$81

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IllegalStateException(5G(&#583#+(nextOR(&/+(previousOR(3*$(A##&(<*00#?1

H/5?(setOE(#R1(l#J0*<#$(83#(0*$8(#0#>#&8(+#8%+&#?(A"(nextOR(/+(previousOR(@583(83#($J#<5G5#?(#0#>#&81(;3#

>#83/?(83+/@$(*&(IllegalStateException(5G(&#583#+(nextOR(&/+(previousOR(3*$(A##&(<*00#?1

8.4.4. Putting Things Together By Examples

4#(&/@(%$#(*(G#@(</?#(#c*>J0#$(8/(500%$8+*8#(3/@(8/(>*&5J%0*8#(05$8$(@583($/>#(/G(83#(*G/+#>#&85/&#?(>#83/?$1

Basic list operations

=&(83#(G5+$8(#c*>J0#(A#0/@-(@#(?#>/&$8+*8#(3/@(8/(<+#*8#(*(05$8-(*??(#0#>#&8$(8/(*&?(+#>/H#(#0#>#&8$(G+/>(*(05$8-

*&?(8+*H#+$#(*(05$8(5&(A/83(?5+#<85/&$(%$5&'(58$(05$8(58#+*8/+1

4/5/21, 10)50 PMIntermediate Programming

Page 139 of 185http://itec2150.gitlab.io/

;3#(/%8J%8(/G(83#(J+/'+*>(5$

importimport java.util.*java.util.*;

publicpublic classclass ListDemo {

publicpublic staticstatic voidvoid main(String[] args) {

List<Integer> arrayList = newnew ArrayList<>();

forfor (intint i = 0; i < 10; i++) {

arrayList.add(i);

}

System.out.println("arrayList:");

System.out.println(arrayList);

arrayList.add(0, 10);

arrayList.add(3, 30);

System.out.println("\narrayList after add(0, 10) and add(3, 30):");

System.out.println(arrayList);

LinkedList<Object> linkedList = newnew LinkedList<>(arrayList);

System.out.println("\nlinkedList:");

System.out.println(linkedList);

linkedList.add(3, "hello");

linkedList.remove(4);

System.out.println("\nlinkedList after add(3, \"hello\") and remove(4):");

System.out.println(linkedList);

linkedList.removeFirst();

linkedList.removeLast();

linkedList.removeFirst();

linkedList.removeLast();

System.out.println("\nlinkedList after the removeFirst and removeLast calls:");

System.out.println(linkedList);

linkedList.addFirst("red");

linkedList.addFirst("green");

linkedList.addFirst("blue");

linkedList.addLast("red");

linkedList.addLast("green");

linkedList.addLast("blue");

System.out.println("\nlinkedList after the addFirst and addLast calls:");

System.out.println(linkedList);

System.out.println("\nDisplay the linked list forward:");

ListIterator<Object> listIterator = linkedList.listIterator();

whilewhile (listIterator.hasNext()) {

System.out.print(listIterator.next() + " ");

}

System.out.println("\n\nDisplay the linked list backward:");

listIterator = linkedList.listIterator(linkedList.size());

whilewhile (listIterator.hasPrevious()) {

System.out.print(listIterator.previous() + " ");

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 140 of 185http://itec2150.gitlab.io/

4#(&/@(#cJ0*5&(83#(*A/H#(</?#(*&?(58$(/%8J%81(U&(N5&#$(M(Q(^-(83#(J+/'+*>(<+#*8#$(arrayList-(*&(#>J8"(*++*"(05$8

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CI(Q(CK-(58(<*00$(arrayList.addOT-(CTR(*&?(arrayList.addOI-(ITR(8/(*??(83#(&#@(#0#>#&8$(CT(*&?(IT(8/(83#(05$8(*8(83#

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</&$8+%<8/+(LinkedListOCollectionx\(#c8#&?$(Ey(<R1(.5&<#(#H#+"(<0*$$(5$(*(?#$<#&?#&8(/G(83#(Object(<0*$$-(835$(05$8

*00/@$(*&"(/AD#<8(8/(A#(*??#?1(F8(835$(J/5&8-(linkedList(*&?(arrayList(</&8*5&(83#($*>#(#0#>#&8$(5&(83#($*>#

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J+5&8(*(05$8-(58(5>J05<580"(8+*H#+$#(83#(05$8(%$5&'(58$(58#+*8/+1

j#c8(/&(N5&#$(EE(Q(EI-(83#(J+/'+*>(<*00$(linkedList.addOI-(r3#00/rR(*&?(linkedList.removeOKR(8/(*??(83#($8+5&'

r3#00/r(*8(5&?#c(I(/G(83#(05$8(*&?(83#&(+#>/H#(83#(#0#>#&8(*8(5&?#c(K(G+/>(83#(+#$%085&'(05$81(FG8#+(r3#00/r(5$(*??#?(*8

5&?#c(I-(83#(#0#>#&8(IT-(@35<3(@*$(*8(5&?#c(I(A#G/+#(linkedList.addOI-(r3#00/rR(@*$(<*00#?-(&/@(>/H#$(8/(5&?#c(K1

;3#+#G/+#-(83#($%A$#d%#&8(<*00(linkedList.removeOKR(+#>/H#$(83#(#0#>#&8(IT(G+/>(83#(05$81

F(<*+#G%0(+#*?#+(>*"(3*H#(&/85<#?(83*8(%&05,#(83#(/AD#<8(arrayList(@35<3(@*$(?#<0*+#?(/&(N5&#(M(*$(*(List-(83#

/AD#<8(linkedList(@*$(?#<0*+#?(/&(N5&#(C[(*$(*(LinkedList1(;35$(5$(A#<*%$#(@#(@*&8(8/(<*00(>#83/?$(/&(58(83*8(*+#

&/8($J#<5G5#?(5&(83#(List(5&8#+G*<#(A%8(J#+8*5&(/&0"(8/(83#(LinkedList(<0*$$1(j#c8(/&(N5&#$(EW(Q(IT-(83#(J+/'+*>(<*00$

linkedList.removeFirstOR(*&?(linkedList.removeLastOR-(83#&(+#J#*8$(83#>1(;35$($#d%#&<#(/G(<*00$(+#>/H#$(83#

G5+$8(8@/(#0#>#&8$(*&?(83#(0*$8(8@/(#0#>#&8$(/G(83#(05$81

arrayList:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

arrayList after add(0, 10) and add(3, 30):

[10, 0, 1, 30, 2, 3, 4, 5, 6, 7, 8, 9]

linkedList:

[10, 0, 1, 30, 2, 3, 4, 5, 6, 7, 8, 9]

linkedList after add(3, "hello") and remove(4):

[10, 0, 1, hello, 2, 3, 4, 5, 6, 7, 8, 9]

linkedList after the removeFirst and removeLast calls:

[1, hello, 2, 3, 4, 5, 6, 7]

linkedList after the addFirst and addLast calls:

[blue, green, red, 1, hello, 2, 3, 4, 5, 6, 7, red, green, blue]

Display the linked list forward:

blue green red 1 hello 2 3 4 5 6 7 red green blue

Display the linked list backward:

blue green red 7 6 5 4 3 2 hello 1 red green blue

4/5/21, 10)50 PMIntermediate Programming

Page 141 of 185http://itec2150.gitlab.io/

j#c8(/&(N5&#$(IK(Q(KT-(83#(J+/'+*>(<*00$(83#(>#83/?$(linkedList.addFirst(*&?(linkedList.addLast(8/(*??($8+5&'$

r+#?r-(r'+##&r(*&?(rA0%#r(8/(83#(G+/&8(*&?(A*<,(/G(83#(05$8(+#$J#<85H#0"1(j/85<#(83*8(addLast(*??$(83#(&#@(#0#>#&8$

8/(A*<,(5&(83#(/+?#+('5H#&-(@3#+#*$(addFirst(*??$(83#(#0#>#&8$(8/(83#(G+/&8(5&(83#(reverse(/+?#+1

V5&*00"(/&(N5&#$(KK(Q(LK-(83#(J+/'+*>(J+5&8$(linkedList(G/+@*+?(*&?(A*<,@*+?-(#cJ05<580"(%$5&'(58$(05$8(58#+*8/+(8/

8+*H#+$#(83#(05$8(5&(A/83(?5+#<85/&$1

Multiple ways to traverse a list

;3#(&#c8(#c*>J0#(5$(*($>5J0#(>#83/?(83*8(</>J%8#$(83#($%>(/G(83#(#0#>#&8$(/G(*(05$81

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F08#+&*85H#0"(*&?(#d%5H*0#&80"-(/&#(<*&(@+58#(83#(>#83/?(%$5&'(*(foreach(0//J(*$(G/00/@$1

F083/%'3(83#(>#83/?(sum2(?/#$(&/8(#cJ05<580"(%$#(*(05$8(58#+*8/+-(83#(foreach(0//J

5>J05<580"(%$#$(83#(58#+*8/+(/G(83#('5H#&(05$8(8/(8+*H#+$#(83#(05$81(;3#+#G/+#-(#H#&(83/%'3(83#"(*+#(@+588#&(?5GG#+#&80"-

83#(>#83/?$(sum(*&?(sum2(*+#(5?#&85<*0(5&(8#+>$(/G(#c#<%85/&1

;3#(G/00/@5&'(5$("#8(*&/83#+(@*"(8/(@+58#(83#(>#83/?1

publicpublic staticstatic intint sum(List<Integer> list) {

intint sum = 0;

ListIterator<Integer> listIterator = list.listIterator();

whilewhile (listIterator.hasNext()) {

sum += listIterator.next();

}

returnreturn sum;

}

JAVA

publicpublic staticstatic intint sum2(List<Integer> list) {

intint sum = 0;

forfor (intint x : list) {

sum += x;

}

returnreturn sum;

}

JAVA

forfor (intint x : list) {

sum += x;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 142 of 185http://itec2150.gitlab.io/

!/@#H#+-(@350#(G%&<85/&*00"(#d%5H*0#&8(8/(sum(*&?(sum2-(83#(>#83/?(sum3($3/%0?(not(A#(%$#?(A#<*%$#(58(5$

inefficient(@3#&(83#('5H#&(05$8(5$(*(linked list1(F$(>#&85/&#?(#*+05#+-(#0#>#&8$(/G(*(05&,#?(05$8(*+#(not(?5+#<80"

*<<#$$5A0#(A"(5&?#c1(;3#+#G/+#-(5&(83#(0//J(/G(sum3-(each(<*00(/G(list.getO5R(+#d%5+#$(*($#*+<3(/H#+(83#(entire(05$8(G/+

83#(#0#>#&8(*8(5&?#c(51(!#&<#(@3#&("/%(&##?(8/(58#+*8#(/H#+(*(05&,#?(05$8-(/+(*(05$8(5&('#&#+*0(@3/$#(8"J#(5$

%&,&/@&-("/%($3/%0?(never do so by indicese(5&$8#*?("/%($3/%0?(#583#+(#cJ05<580"(%$#(83#(iterator(/G(83#(05$8-(/+(%$#

*(foreach(0//J(83*8(@/%0?(%$#(83#(05$8(58#+*8/+(5>J05<580"1

F(foreach(0//J(5$(&5<#(A#<*%$#(58(5$(#GG5<5#&8(*&?(*0$/($5>J05G5#$(83#(</?#(@3#&(58(5$(*JJ05<*A0#1(!/@#H#+-(/&#

05>58*85/&(/G(*(foreach(0//J(5$(83*8(58(only(*00/@$("/%(8/(*<<#$$(*(?*8*($8+%<8%+#(A%8(?/#$(not(*00/@("/%(8/(>/?5G"(581

;3#+#G/+#-(8/(#GG5<5#&80"($#*+<3(*&?(%J?*8#(*&(#&85+#(05$8-("/%(>*"($8500(&##?(8/(%$#(58$(58#+*8/+(#cJ05<580"1

Using an iterator to add and remove - an illustration

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=&(83#(0*$8(#c*>J0#(/G(83#($#<85/&-(@#(@+58#(*(>#83/?

83*8(*??$(83#($J#<5G5#?(#0#>#&8(*8(83#($J#<5G5#?(5&?#c(/G(83#('5H#&(05$81(;3#(#GG#<8(/G(addAtIndexOlist-(5&?#c-

#0#>#&8R(5$(5?#&85<*0(8/(83*8(/G(list.addO5&?#c-(#0#>#&8R1(!/@#H#+-(addAtIndexOlist-(5&?#c-(#0#>#&8R(?/#$(not(<*00

List.addO5&?#c-(#0#>#&8R(/+(%$#(*&"(>#83/?(/G(83#(05$8(/83#+(83*&(58$(05$8(58#+*8/+1(=8(/&0"(<*00$(83+##(>#83/?$(/G(83#

publicpublic staticstatic intint sum3(List<Integer> list) {

intint sum = 0;

forfor (intint i = 0; i < list.size(); i++) {

sum += list.get(i);

}

returnreturn sum;

}

JAVA

publicpublic staticstatic voidvoid removeOdds(List<Integer> list) {

ListIterator<Integer> listIterator = list.listIterator();

whilewhile (listIterator.hasNext()) {

intint x = listIterator.next();

ifif (x % 2 != 0) {

listIterator.remove();

}

JAVA

<E> voidvoid addAtIndex(List<E> list, intint index, E element)

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 143 of 185http://itec2150.gitlab.io/

05$8(58#+*8/+B(nextIndexOR-(nextOR(*&?(addOR1(;3#+#G/+#-(83#(</?#(500%$8+*8#$(3/@(8/(5>J0#>#&8(83#(addO5&?#c-

#0#>#&8R(>#83/?(G/+(*(05$8(%$5&'(58$(58#+*8/+(/&0"1

;3#(>#83/?(83+/@$(*&(=&?#cU%8UG`/%&?$bc<#J85/&(5G(83#($J#<5G5#?(5&?#c(5$(/%8$5?#(83#(H*05?(+*&'#(/G(5&?5<#$1(=G

83#(5&?#c(5$(@5835&(83#(H*05?(+*&'#-(83#(@350#(0//J(*?H*&<#$(83#(<%+$/+(/G(83#(05$8(58#+*8/+(%&850(83#(J/$585/&

5>>#?5*8#0"(A#G/+#(83#(#0#>#&8(<%++#&80"(/<<%J"5&'(83#(5&?#c(5G(83#(5&?#c(x(05$81$5a#OR-(/+(8/(83#(#&?(/G(83#(05$8(5G

83#(5&?#c(#d%*0$(05$81$5a#OR1(U&<#(83#(>#83/?(#c58$(83#(0//J-(58(*??$(83#($J#<5G5#?(#0#>#&8(*8(83#(+5'38(J0*<#1

;3#(*A/H#(5>J0#>#&8*85/&(/G(83#(>#83/?(*0@*"$($8*+8$(83#(05$8(58#+*8/+(*8(83#(G+/&8(/G(83#(05$81(=8(5$($0/@(@3#&(83#

$J#<5G5#?(5&?#c(5$(&#*+(83#(A*<,(/G(83#(05$81(U&#(<*&(>*,#(*&(5>J+/H#>#&8(8/(83#(>#83/?(A"($8*+85&'(83#(58#+*8/+(*8

83#(#&?(83*8(5$(<0/$#+(8/(83#($J#<5G5#?(5&?#c1(4#(0#*H#(835$(*$(*&(#c#+<5$#1

8.4.5. Notes on Eﬃciency: Array List vs. Linked List

4#(</&<0%?#(83#($#<85/&(/&(05$8$(@583($/>#(+#>*+,$(/&(83#(#GG5<5#&<"(/G(*++*"(05$8$(*&?(05&,#?(05$8$1(F<<#$$5&'

#0#>#&8$(/G(*&(*++*"(05$8(A"(5&?#c(5$(H#+"(#GG5<5#&8(A#<*%$#(58$(A*<,5&'(?*8*($8+%<8%+#(5$(*&(*++*"1(U&(83#(/83#+

3*&?-(*$(*0+#*?"(>#&85/&#?-(*<<#$$5&'(#0#>#&8$(/G(*(05&,#?(05$8(A"(5&?#c(5$(H#+"(5&#GG5<5#&8-(A#<*%$#(58(+#d%5+#$(8/

$#*+<3(83#(#&85+#(05$8(G/+(83#(5&?#c1(7/&$#d%#&80"-(G/+(*JJ05<*85/&$(83*8(+#d%5+#(>*&"(random accesses(8/(83#

#0#>#&8$(/G("/%+(05$8-(*&(*++*"(05$8(5$(J+#G#++#?1

U&(83#(/83#+(3*&?-(*(05&,#?(05$8(5$(>/+#(#GG5<5#&8(G/+(*??5&'(8/(/+(+#>/H5&'(G+/>(83#(two ends(/G(83#(05$81(V/+(*&

*++*"(05$8-(@350#(+#>/H5&'(G+/>(83#(A*<,(5$(G*$8(*&?(*??5&'(8/(83#(A*<,(5$(%$%*00"(G*$8-(*??5&'(8/(83#(G+/&8(/+

+#>/H5&'(G+/>(83#(G+/&8(5$(H#+"($0/@(*$(58(+#d%5+#$(8/($35G8(83#(#&85+#(05$81

N5$8$(*+#(83#($5>J0#$8('#&#+*0QJ%+J/$#(?*8*($8+%<8%+#$(83*8(*00/@(/&#(8/($#*+<3(G/+(*&?(%J?*8#(#0#>#&8$-(*??(&#@

#0#>#&8$(*&?(+#>/H#(#c5$85&'(#0#>#&8$1(!/@#H#+(all(83#(>#83/?$(/G(*(05$8(+#d%5+5&'(*($#*+<3(/G(*&(#0#>#&8-(*+#

inefficient-(@3#83#+(83#(%&?#+0"5&'(05$8(5$(*&(*++*"(05$8(/+(*(05&,#?(05$81(;3#$#(>#83/?$(5&<0%?#(containsOObject(/R-

removeOObject(/R-(indexOfOObject(/R-(*&?($#H#+*0(/83#+$1(=&(83#(@/+$8(<*$#(/&#(&##?$(8/($#*+<3(83#(#&85+#(05$8(G/+

83#('5H#&(/AD#<8(/G(5&8#+#$81(;3#+#G/+#-(05$8$(*+#(&/8(5?#*0(G/+(83#(>*&"(*JJ05<*85/&$(83*8(+#d%5+#(*(0*+'#(&%>A#+(/G

$#*+<3-(%J?*8#-(5&$#+85/&(*&?(?#0#85/&(/J#+*85/&$1(V/+($%<3(*JJ05<*85/&$("/%(@/%0?(?#$5+#(*&(#GG5<5#&8(?*8*

$8+%<8%+#($%<3(*$(*(hash map(/+(*(balanced binary search tree-(@35<3("/%(@500(0#*+&(5&(=;b7(ICLTB(F?H*&<#?

)+/'+*>>5&'1

8.5. Stacks

publicpublic staticstatic <E> voidvoid addAtIndex(List<E> list, intint index, E element) {

ifif (index < 0 || index > list.size()) {

throwthrow newnew IndexOutOfBoundsException("Index " + index + " is out of bound");

}

ListIterator<E> listIterator = list.listIterator();

whilewhile (listIterator.nextIndex() < index) {

listIterator.next();

}

listIterator.add(element);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 144 of 185http://itec2150.gitlab.io/

F($8*<,(5$(*(H#+"($J#<5*0(05$8(@583(/&#(#&?(r<0/$#?r-($/(83*8(58(5$(/&0"(*<<#$$5A0#(G+/>(83#(/83#+(#&?1(;/(H5$%*05a#(*

$8*<,-(@#(#&H5$5/&(*(H#+85<*0($8*<,(/G(J0*8#$-(@3#+#(*??5&'(/+(+#>/H5&'(5$(/&0"(J/$$5A0#(*8(83#(8/J1(.##(83#(G/00/@5&'

5>*'#(G+/>(45,5J#?5* O388J$BPP#&1@5,5J#?5*1/+'P@5,5P.8*<,YO*A$8+*<8Y?*8*Y8"J#RR1

F($8*<,(3*$(8@/(G%&?*>#&8*0(/J#+*85/&$B

push-(@35<3(*??$(*&(#0#>#&8(8/(83#(8/J(/G(83#($8*<,e(*&?

pop-(@35<3(+#>/H#$(83#(#0#>#&8(*8(83#(8/J(/G(83#($8*<,1

V/+(</&H#&5#&<#-(*(peek(/J#+*85/&(5$(5&8+/?%<#?(83*8(*00/@$(/&#(8/(+#*?(83#(#0#>#&8(*8(83#(8/J(@583/%8(+#>/H5&'

581

`#<*%$#(*($8*<,(5$(/&0"(*<<#$$5A0#(G+/>(83#(8/J-(58(3*$(83#(J+/J#+8"(,&/@&(*$(last in, first out(OLIFOR1(;3*8(5$-(83#

0*$8(#0#>#&8(83*8(#&8#+$(83#($8*<,(5$(83#(G5+$8(#0#>#&8(83*8(</>#$(/%81(=&(/83#+(@/+?$-(#H#+"(85>#(83#($8*<,(5$

J/JJ#?-(83#(#0#>#&8(83*8(</>#$(/%8(5$(83#(>/$8(+#<#&80"(*??#?(#0#>#&8(5&(83#($8*<,(*8(83*8(85>#1

8.5.1. The Stack Class

;3#(Stack(<0*$$(5$(>%<3($5>J0#+(83*&(83#(LinkedList(/+(83#(ArrayList(<0*$$1(9/%(<*&(G5&?(*(?#8*50#?(?#$<+5J85/&(/G

83#(StackxEy(<0*$$(*8(388J$BPP?/<$1/+*<0#1</>PD*H*$#P[P?/<$P*J5PD*H*P%850P.8*<,138>01(`#0/@(@#($%>>*+5a#(83#

5>J/+8*&8(>#83/?$(/G(83#(<0*$$1

E(pushOE(#R1(F??$(83#($J#<5G5#?(#0#>#&8(8/(83#(8/J(/G(83#($8*<,(*&?(+#8%+&$(83#(*??#?(#0#>#&81

4/5/21, 10)50 PMIntermediate Programming

Page 145 of 185http://itec2150.gitlab.io/

E(popOE(#R1(l#>/H#$(*&?(+#8%+&$(83#(#0#>#&8(*8(83#(8/J(/G(83#($8*<,1(;3#(>#83/?(83+/@$(*&

EmptyStackException(5G(83#($8*<,(5$(#>J8"1

E(peekOE(#R1(l#8%+&$(83#(#0#>#&8(*8(83#(8/J(/G(83#($8*<,(@583/%8(+#>/H5&'(581(;3#(>#83/?(83+/@$(*&

EmptyStackException(5G(83#($8*<,(5$(#>J8"1

A//0#*&(addAllOCollectionx\(#c8#&?$(Ey(<R1(F??$(*00(83#(#0#>#&8$(/G(83#($J#<5G5#?(</00#<85/&(8/(83#($8*<,(5&(83#

/+?#+(?#G5&#?(A"(83#(</00#<85/&m$(58#+*8/+-(*&?(+#8%+&$(true(5G(*00(83#(#0#>#&8$(*+#($%<<#$$G%00"(*??#?1(;3#

>#83/?(83+/@$(*(NullPointerException(5G(83#($J#<5G5#?(</00#<85/&(5$(null1

5&8(sizeOR1(l#8%+&$(83#($5a#(/G(83#($8*<,-(51#1(83#(&%>A#+(/G(#0#>#&8$(5&(83#($8*<,1

A//0#*&(emptyOR1(l#8%+&$(true(5G(*&?(/&0"(5G(83#($8*<,(5$(#>J8"(O51#1($5a#OR(]](TR1

H/5?(clearOR1(70#*+$(83#($8*<,1

;3#(H#+"($5>J0#(</?#(A#0/@($3/@$(3/@(8/(<+#*8#(*(Stack(/AD#<8(*&?(%$#(58$(>#83/?$1

;3#(G/00/@5&'(5$(83#(/%8J%8(/G(83#(J+/'+*>-(@35<3(?#>/&$8+*8#$(83#(LIFO(&*8%+#(/G(*($8*<,

=&8#'#+$(C(8/(M(*+#(*??#?(8/(83#($8*<,(5&(835$(/+?#+1(;3#"(</>#(/%8(5&(83#(reverse(/+?#+(?%#(8/(83#(LIFO(&*8%+#(/G

83#($8*<,1(;3#(G/00/@5&'(5>*'#(G+/>(45,5J#?5* O388J$BPP#&1@5,5J#?5*1/+'P@5,5P.8*<,YO*A$8+*<8Y?*8*Y8"J#RR(?#>/&$8+*8#$(83#

$8#J$(5&(83#(#c#<%85/&(/G(83#(J+/'+*>1

importimport java.util.*java.util.*;

publicpublic classclass StackDemo {

publicpublic staticstatic voidvoid main(String[] args) {

Stack<Integer> stack = newnew Stack<>();

forfor (intint i = 1; i <= 6; i++) {

stack.push(i);

}

System.out.println("Stack after elements are added: ");

System.out.println(stack);

System.out.println();

System.out.println("Popping the stack: ");

whilewhile (!stack.empty()) {

System.out.print(stack.pop() + " ");

}

JAVA

Stack after elements are added:

[1, 2, 3, 4, 5, 6]

Popping the stack:

6 5 4 3 2 1

4/5/21, 10)50 PMIntermediate Programming

Page 146 of 185http://itec2150.gitlab.io/

8.5.2. Applications of Stacks

F(<%+5/%$(+#*?#+(>*"(*$,(*8(835$(J/5&8(@3"(@#(<*+#(*A/%8(83#(LIFO(J+/J#+8"(*&?(@3*8(&/&8+5H5*0(8*$,$(@#(<*&

*<</>J05$3(@583(*($8*<,1(=8(8%+&$(/%8(83*8($8*<,$(*+#($%+J+5$5&'0"(%$#G%0(*&?(J/@#+G%0(5&(J+/'+*>>5&'(?#$J58#(83#5+

$5>J05<58"1(!#+#(@#(H#+"(A+5#G0"(>#&85/&($/>#(5>J/+8*&8(*JJ05<*85/&$(/G($8*<,$(5&(&/&8#<3&5<*0(8#+>$1

F($8*<,(5$(%$#?(8/(5>J0#>#&8(83#(undo(G%&<85/&(/G(*JJ05<*85/&$($%<3(*$(S5<+/$/G8(4/+?1(;3#(*JJ(J%$3#$(*00(83#

*<85/&$(8/(*($8*<,(*$(83#"(/<<%+1(43#&(83#(%$#+(J+#$$#$(83#(undo(A%88/&-(83#(*JJ(J/J$(83#($8*<,(8/(%&?/(83#(>/$8

+#<#&8(*<85/&1

F(0#$$(/AH5/%$(*JJ05<*85/&(5$(J+/'+*>(#c#<%85/&1(43#&(*(J+/'+*>(5$(#c#<%8#?-(83#(+%&85>#($"$8#>(%$#$(*(call stack

8/(#c#<%8#(58$(G%&<85/&$(/+(>#83/?$1(l/%'30"($J#*,5&'-(83#(<*00($8*<,(>*5&8*5&$(*00(83#(*<85H#(>#83/?$(*@*585&'

#c#<%85/&1(;3#(>#83/?(*8(83#(8/J(/G(83#($8*<,(5$(83#(&#c8(/&#(8/(#c#<%8#1(43#&(*(>#83/?(O83#(callerR(5&(#c#<%85/&

<*00$(*&/83#+(>#83/?(O83#(calleeR-(83#(<*00#+(3*$(8/($%$J#&?(58$(#c#<%85/&(%&850(83#(<*00##(+#8%+&$1(;3#+#G/+#-(83#

+%&85>#($"$8#>(J%$3#$(83#(<*00#+(8/(83#(8/J(/G(83#($8*<,(*&?(#c#<%8#$(83#(<*00##1(43#&(83#(<*00##(+#8%+&$-(83#

$"$8#>(J/J$(83#($8*<,(*&?(+#$%>#$(83#(#c#<%85/&(/G(83#(<*00#+1

=&(73*J8#+(W("/%(0#*+&#?(83#(J/@#+G%0(8#<3&5d%#(/G(recursion(83*8($/0H#$(J+/A0#>$(@583(*(?5H5?#Q*&?Q</&d%#+

$8+*8#'"-(@3#+#(*(>#83/?(,##J$(<*005&'(58$#0G(%&850(*(A*$#(<*$#(5$(+#*<3#?1(V+/>(83#(J+#<#?5&'(J*+*'+*J3("/%(<*&

$##(83*8(*($8*<,(5$(#$$#&85*0(G/+(83#(#c#<%85/&(/G(*00(+#<%+$5H#(>#83/?$1

.8*<,$(*+#(</>>/&0"(%$#?(8/(5>J0#>#&8(*(G%&?*>#&8*0(*0'/+583>(,&/@&(*$(Depth First Search(O2V.R(83*8("/%(@500

0#*+&(5&(=;b7(ICLTB(F?H*&<#?()+/'+*>>5&'1(F>/&'(>*&"(/83#+(*JJ05<*85/&$-(2V.(5$(<+%<5*0(G/+(%&</H#+5&'

5>J/+8*&8(J+/J#+85#$(*&?($8+%<8%+#$(/G(0*+'#-($/J35$85<*8#?(</>J%8#+(/+($/<5*0(&#8@/+,$1(=8(5$(%$#?-(G/+(#c*>J0#-(A"

$#*+<3(#&'5&#$(8/(<+*@0(83#(4#A1

9#8(*&/83#+(*JJ05<*85/&(5$(J*+$5&'(5&(J+/'+*>(</>J50*85/&1(43#&(83#($/%+<#(</?#(/G(*(J+/'+*>(5$(</>J50#?-(83#

J*+$#+(/G(83#(</>J50#+(%$#$(*($8*<,(8/(J*+$#(83#(#cJ+#$$5/&$(*&?($8*8#>#&8$(5&(83#(</?#(G/+($"&8*c(#++/+$1

4/5/21, 10)50 PMIntermediate Programming

Page 147 of 185http://itec2150.gitlab.io/

;3#(*A/H#>#&85/&#?(*JJ05<*85/&$(*+#($/J35$85<*8#?(*&?(A#"/&?(83#($</J#(/G(835$(</%+$#1(j#c8(@#(J+#$#&8(*

<0*$$5<*0(J+/A0#>(83*8(5$($8500(&/&8+5H5*0(A%8(<*&(A#(+#*?50"($/0H#?(%$5&'(*($8*<,1

8.5.3. A Classical Application: Checking for Balanced Parentheses

4#(</&<0%?#(83#($#<85/&(/&($8*<,$(@583(*(<0*$$5<*0(J*+$5&'(J+/A0#>(83*8(5$(*>#&*A0#(8/(*($8*<,1

4#(</&$5?#+(3#+#(*($#d%#&<#(/G(J*+#&83#$#$(oOo(*&?(oRo1(;3#($*>#(*JJ05#$(8/(o•o(*&?(o€o-(/+(ozo(*&?(o}o1(F($#d%#&<#(/G

J*+#&83#$#$(5$(balanced(5G(#H#+"(oRo(<0/$#$(*(J+#<#?5&'(oOo-(*&?(</&H#+$#0"(#H#+"(oOo(5$(<0/$#?(A"(*($%A$#d%#&8(oRo(5&(83#

$#d%#&<#1(V/+(#c*>J0#-($#d%#&<#$(O(R-(O(RO(R-(O(O(R(R-(*&?(O(O(R(O(R(R(O(R(*+#(*00(A*0*&<#?-(@3#+#*$($#d%#&<#$(RO-(O(R(R-(O(O(R(*&?

O(RO(R(R(*+#(&/8(A*0*&<#?1(;3#(J+/A0#>(/G(5&8#+#$8(3#+#(5$(8/(?#<5?#(@3#83#+(*('5H#&($#d%#&<#(/G(J*+#&83#$#$(5$

A*0*&<#?1(;3#(J+/A0#>(</>#$(%J(5&(83#(J*+$5&'(/G(J+/'+*>$(G/+($"&8*c(#++/+$1(O7*&("/%($##(3/@(835$(5$(+#0#H*&8\R

;3#(J+/A0#>(?/#$(&/8(*JJ#*+(#*$"(*$(58(>*"($##>(3*+?(8/(G5&?(>*8<35&'(J*5+$(/G(oOo(*&?(oRo1(;3#(,#"(/A$#+H*85/&(5$(5G

*($#d%#&<#(5$(A*0*&<#?-(83#&(*$(@#(J+/<#$$(58(G+/>(0#G8(8/(+5'38-(#H#+"(oRo(<0/$#$(83#(last(J+#<#?5&'(oOo(83*8(+#>*5&$(8/

A#(<0/$#?1(;35$(5$(LIFOn(4583(835$(5?#*(5&(>5&?-(@#(3*H#(83#(G/00/@5&'($5>J0#(>#83/?(83*8($/0H#$(83#(J+/A0#>1

4#(*$$%>#(83*8(#H#+"(<3*+*<8#+(5&(83#(5&J%8($8+5&'(5$(#583#+(oOo(/+(oRo1(;3#(>#83/?(J+/<#$$#$(83#(5&J%8(G+/>(0#G8(8/

+5'381(ZJ/&($##5&'(#*<3(oOo-(83#(>#83/?(J%$3#$(58(8/(83#($8*<,1(ZJ/&($##5&'(*(oRo-(83#(>#83/?(*88#>J8$(8/(G5&?(*

>*8<35&'(oOo(A"(J/JJ5&'(83#($8*<,1(=G(*8(835$(J/5&8(83#($8*<,(5$(#>J8"(OA#G/+#(83#(@3/0#(5&J%8(5$(J+/<#$$#?R-(83#&(83#

<%++#&8(<3*+*<8#+(5$(*&(/%8$8*&?5&'(oRo(83*8(?/#$(&/8(<0/$#(*(J+#<#?5&'(oOo1(;3#+#G/+#-(83#(5&J%8(5$(&/8(A*0*&<#?(*&?

83#(>#83/?(+#8%+&$(G*0$#1(=G(83#(>#83/?(#c58$(83#(0//J(*G8#+(J+/<#$$5&'(83#(@3/0#(5&J%8(A%8(83#($8*<,(5$(not(#>J8"-

83#&(83#+#(5$($/>#(/%8$8*&?5&'(oOo(#*+0"(5&(83#(5&J%8(83*8(5$(&/8(<0/$#?(A"(*($%A$#d%#&8(oRo1(;3#+#G/+#-(83#(5&J%8(5$

A*0*&<#?(5G(*&?(/&0"(5G(83#($8*<,(5$(#>J8"(*G8#+(83#(@3/0#(5&J%8(5$(J+/<#$$#?1(;35$(5$(@3*8(83#(>#83/?(+#8%+&$1

=&(/&#(/G(83#(#c#+<5$#$-("/%(@500(A#(*$,#?(8/(%$#(*($8*<,(8/($/0H#(*(H*+5*&8(/G(83#(J+/A0#>-(@3#+#(oOo-(oRo-(o•o-(o€o-(ozo(*&?

o}o(</%0?(*00(A#(J+#$#&8(5&(83#(5&J%81(;35$(3*$(A##&(*(J/J%0*+(5&8#+H5#@(d%#$85/&$(G/+(J/$585/&$(5&(83#($/G8@*+#

5&?%$8+"n

8.6. Queues

publicpublic staticstatic booleanboolean isBalanced(String parentheses) {

Stack<Character> stack = newnew Stack<>();

forfor (charchar p : parentheses.toCharArray()) {

ifif (p == '(') {

stack.push(p);

}

elseelse {

// i.e. if p == ')'

ifif (stack.empty()) {

returnreturn falsefalse;

}

stack.pop();

}

returnreturn stack.empty();

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 148 of 185http://itec2150.gitlab.io/

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d%#%#1

Dequeue

Enqueue

Back Front

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8.6.1. The Queue Interface

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4/5/21, 10)50 PMIntermediate Programming

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8.6.2. Applications of Queues

N5,#($8*<,$-(d%#%#$(3*H#(>*&"(5>J/+8*&8(*JJ05<*85/&$(?#$J58#(83#5+($5>J05<58"1(2%#(8/(83#5+(FIFO(&*8%+#-(d%#%#$

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$#+H#?(/&(*(first come, first serve(A*$5$1

importimport java.util.*java.util.*;

publicpublic classclass QueueDemo {

publicpublic staticstatic voidvoid main(String[] args) {

Queue<Integer> queue = newnew LinkedList<>();

forfor (intint i = 1; i <= 6; i++) {

queue.add(i);

}

System.out.println("Queue after elements are added: ");

System.out.println(queue);

System.out.println();

System.out.println("Emptying the queue: ");

whilewhile (!queue.isEmpty()) {

System.out.print(queue.remove() + " ");

}

JAVA

Queue after elements are added:

[1, 2, 3, 4, 5, 6]

Emptying the queue:

1 2 3 4 5 6

4/5/21, 10)50 PMIntermediate Programming

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8.7. Priority Queues

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8.7.1. The PriorityQueue Class

4/5/21, 10)50 PMIntermediate Programming

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F8(388J$BPP?/<$1/+*<0#1</>PD*H*$#P[P?/<$P*J5PD*H*P%850P)+5/+58"p%#%#138>0("/%(<*&(G5&?(*(?#8*50#?(?#$<+5J85/&(/G(83#

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ClassCastException1

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d%#%#(A"(J*$$5&'(Collections.reverseOrder()(*$(83#(</>J*+*8/+1

4/5/21, 10)50 PMIntermediate Programming

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8.7.2. The Comparator Interface

importimport java.util.*java.util.*;

publicpublic classclass PQDemo {

publicpublic staticstatic voidvoid main(String[] args) {

PriorityQueue<Integer> pq1 = newnew PriorityQueue<>();

pq1.add(5); pq1.add(3); pq1.add(2);

pq1.add(6); pq1.add(4); pq1.add(1);

System.out.print("Emptying pq1: ");

whilewhile (!pq1.isEmpty()) {

System.out.print(pq1.remove() + " ");

}

PriorityQueue<Integer> pq2 = newnew PriorityQueue<>(Collections.reverseOrder());

pq2.add(5); pq2.add(3); pq2.add(2);

pq2.add(6); pq2.add(4); pq2.add(1);

System.out.print("\n\nEmptying pq2: ");

whilewhile (!pq2.isEmpty()) {

System.out.print(pq2.remove() + " ");

}

PriorityQueue<String> pq3 = newnew PriorityQueue<>(

Arrays.asList("Shanghai", "Boston", "New York", "Zurich", "Atlanta"));

System.out.print("\n\nEmptying pq3: ");

whilewhile (!pq3.isEmpty()) {

System.out.print(pq3.remove() + " ");

}

JAVA

Emptying pq1: 1 2 3 4 5 6

Emptying pq2: 6 5 4 3 2 1

Emptying pq3: Atlanta Boston New York Shanghai Zurich

4/5/21, 10)50 PMIntermediate Programming

Page 153 of 185http://itec2150.gitlab.io/

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=&(83#(<0*$$(*00(@#(&##?(8/(?/(5$(8/(5>J0#>#&8(83#(compare(>#83/?1(=G(83#(J*+*>#8#+$(s1(*&?(s2(3*H#(different

0#&'83$-(83#&(83#(compare(>#83/?(?#8#+>5&#$(83#5+(/+?#+(A"(0#&'831(=&(835$(<*$#(83#(>#83/?(+#8%+&$

j/85<#(83*8(5G(s1(5$($3/+8#+(83*&(s2-(83#&(83#(+#8%+&#?(H*0%#(s1.length() - s2.length()(5$(&#'*85H#-(83#+#G/+#(s1

J+#<#?#$(s2(5&(83#(&#@(/+?#+1(7/&H#+$#0"-(5G(s1(5$(0/&'#+(83*&(s2-(83#&(83#(+#8%+&#?(H*0%#(s1.length() - s2.length()

5$(J/$585H#-(83#+#G/+#(s2(J+#<#?#$(s1(5&(83#(&#@(/+?#+1

=G(s1(*&?(s2(3*H#(83#($*>#(0#&'83-(83#&(83#(compare(>#83/?(+#8%+&$

publicpublic intint compare(T o1, To2)

JAVA

classclass StringLenComparator implementsimplements Comparator<String> {

publicpublic intint compare(String s1, String s2) {

ifif (s1.length() != s2.length()) {

returnreturn s1.length() - s2.length();

}

elseelse {

returnreturn s1.compareTo(s2);

}

JAVA

s1.length() - s2.length()

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 154 of 185http://itec2150.gitlab.io/

@35<3(/+?#+$(83#(8@/($8+5&'$(A"(83#(&*8%+*0(/+?#+5&'(/G(83#(String(<0*$$1

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StringLenComparator1(=8(?/#$($/(A"(J*$$5&'(8/(83#(</&$8+%<8/+(*&(/AD#<8(/G(83#(StringLenComparator(*$(83#

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;3#($8+5&'(rl#?r-(@35<3(5$(/G(0#&'83(I-(5$(83#($3/+8#$8(/G(*00(83#($8+5&'$(5&(83#(05$81(;3#+#G/+#-(rl#?r(*JJ#*+$(G5+$8(*$

#0#>#&8$(*+#(+#>/H#?(G+/>(83#(J+5/+58"(d%#%#(pq1(=8(5$(G/00/@#?(A"(r`0%#r-(r7"*&r(*&?(rq/0?r-(#*<3(/G(0#&'83(K1

`#<*%$#(83#"(3*H#(83#($*>#(0#&'83-(83#"(*+#(/+?#+(*0J3*A#85<*00"(*>/&'(83#>1(;3#"(*+#(G/00/@#?(A"(rq+##&r

@35<3(5$(/G(0#&'83(L1(;3#($8+5&'(rq+##&r(5$(G/00/@#?(A"(r=&?5'/r-(rU+*&'#r-(r)%+J0#r-(rh5/0#8r(*&?(r9#00/@r-(#*<3(/G

@35<3(5$(/G(0#&'83(M1(F'*5&(A#<*%$#(83#$#(G5H#(*+#(/G(83#($*>#(0#&'83-(83#"(*+#(/+?#+(*0J3*A#85<*00"(*>/&'(83#>1(=&

83#(>#*&85>#-("/%($##(83*8(83#($*>#($8+5&'$(</>#(/%8(5&(83#(*0J3*A#85<(/+?#+(*$(83#"(0#*H#(83#(J+5/+58"(d%#%#(pq21

F08#+&*85H#0"-(@#(<*&(%$#(*(lambda expression(8/(?#G5&#(83#(</>J*+*8/+(*&?($5>J05G"(83#(*A/H#(</?#-(*$(G/00/@$1

s1.compareTo(s2)

JAVA

publicpublic classclass ComparatorDemo1 {

publicpublic staticstatic voidvoid main(String[] args) {

List<String> list = Arrays.asList(

"Violet", "Indigo", "Blue", "Green", "Yellow", "Orange", "Red", "Cyan", "Gold", "Purple");

PriorityQueue<String> pq = newnew PriorityQueue<>(newnew StringLenComparator());

pq.addAll(list);

System.out.println("Order imposed by the new comparator: ");

whilewhile (!pq.isEmpty()) {

System.out.print(pq.remove() + " ");

}

System.out.println("\n\nNatural order: ");

PriorityQueue<String> pq2 = newnew PriorityQueue<>();

pq2.addAll(list);

whilewhile (!pq2.isEmpty()) {

System.out.print(pq2.remove() + " ");

}

JAVA

Order imposed by the new comparator:

Red Blue Cyan Gold Green Indigo Orange Purple Violet Yellow

Natural order:

Blue Cyan Gold Green Indigo Orange Purple Red Violet Yellow

4/5/21, 10)50 PMIntermediate Programming

Page 155 of 185http://itec2150.gitlab.io/

4#(&/@(+#8%+&(8/(83#(#>#+'#&<"(+//>(#c*>J0#(83*8(@*$(?5$<%$$#?(*8(83#(A#'5&&5&'(/G(83#($#<85/&1(.%JJ/$#(83*8

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H*0%#(/G(arrival-(83#(#*+05#+(83#(J*85#&8(*++5H#?1

4#(&/@(?#G5&#(*&(/+?#+5&'(/G(J*85#&8$(5&(/+?#+(8/(?#<5?#(83#(/+?#+(8/(*?>58(83#>1(4#(first order patients by

severity in descending order1(;3*8(5$-(J*85#&8$(@583(*(35'3#+($#H#+58"(H*0%#($3/%0?(A#($##&(#*+05#+1(=G(8@/(J*85#&8$

3*H#(83#($*>#(severity(H*0%#-(@#(then order them by arrival in ascending order1(;3*8(5$-(J*85#&8$(@583(83#($*>#

importimport java.util.*java.util.*;

publicpublic classclass ComparatorDemo2 {

publicpublic staticstatic voidvoid main(String[] args) {

List<String> list = Arrays.asList(

"Violet", "Indigo", "Blue", "Green", "Yellow", "Orange", "Red", "Cyan", "Gold", "Purple");

Comparator<String> cmp = (s1, s2) -> {

ifif (s1.length() != s2.length()) {

returnreturn s1.length() - s2.length();

}

elseelse {

returnreturn s1.compareTo(s2);

}

};

PriorityQueue<String> pq = newnew PriorityQueue<>(cmp);

pq.addAll(list);

System.out.println("Order imposed by the new comparator: ");

whilewhile (!pq.isEmpty()) {

System.out.print(pq.remove() + " ");

}

JAVA

classclass Patient {

String name;

intint arrival;

intint severity;

publicpublic Patient(String name, intint arrival, intint severity) {

thisthis.name = name;

thisthis.arrival = arrival;

thisthis.severity = severity;

}

publicpublic String toString() {

returnreturn String.format("(%s, %d, %d)", name, arrival, severity);

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 156 of 185http://itec2150.gitlab.io/

0#H#0(/G($#H#+58"(*+#($##&(/&(83#(G5+$8(</>#-(G5+$8($#+H#(A*$5$1(;3#(G/00/@5&'(J+/'+*>(5>J0#>#&8$(835$(/+?#+5&'1

;3#(J+/'+*>(<+#*8#$(*(</>J*+*8/+(cmp(83*8(</>J*+#$(J*85#&8$(A"(83#(/+?#+5&'($J#<5G5#?(*A/H#1(j/85<#(83*8(@3#&

J*85#&8$(p1(*&?(p2(3*H#(?5GG#+#&8(H*0%#$(G/+(severity-(83#(</>J*+*8/+(+#8%+&$(p2.severity - p1.severity-(not

JC1$#H#+58"(Q(JE1$#H#+58"1(;35$(5$(A#<*%$#(83#(J*85#&8$(*+#(8/(A#(/+?#+#?(G5+$8(5&(?#$<#&?5&'(/+?#+(/G(severity1(=G

83#&

83#+#G/+#(+#8%+&5&'(p2.severity - p1.severity(@500(>*,#(p1(J+#<#?#(p21

;3#(G/00/@5&'(5$(83#(/%8J%8(/G(83#(J+/'+*>1

importimport java.util.*java.util.*;

publicpublic classclass ER {

publicpublic staticstatic voidvoid main(String[] args) {

List<Patient> list = Arrays.asList(

newnew Patient("Alice", 1, 6), newnew Patient("Bob", 2, 9), newnew Patient("Carol", 3, 8),

newnew Patient("Frank", 4, 7), newnew Patient("Eve", 5, 8), newnew Patient("Dan", 6, 7));

Comparator<Patient> cmp = (p1, p2) -> {

ifif (p1.severity != p2.severity) {

returnreturn p2.severity - p1.severity;

}

elseelse {

returnreturn p1.arrival - p2.arrival;

}

};

PriorityQueue<Patient> pq = newnew PriorityQueue<>(cmp);

pq.addAll(list);

System.out.println("Order to admit the patients: ");

whilewhile (!pq.isEmpty()) {

System.out.print(pq.remove() + " ");

}

JAVA

p1.severity > p2.severity,

JAVA

p2.severity - p1.severity < 0,

JAVA

Order to admit the patients:

(Bob, 2, 9) (Carol, 3, 8) (Eve, 5, 8) (Frank, 4, 7) (Dan, 6, 7) (Alice, 1, 6)

4/5/21, 10)50 PMIntermediate Programming

Page 157 of 185http://itec2150.gitlab.io/

`/A(*JJ#*+$(G5+$8(A#<*%$#(3#(3*$(83#(35'3#$8($#H#+58"(H*0%#(^1(!#(5$(G/00/@#?(A"(7*+/0(*&?(bH#(@3/(A/83(3*H#(83#

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3*$(83#(0/@#$8($#H#+58"(H*0%#(M1

8.7.3. Applications of Priority Queues

;3#(>/$8(?5+#<8(*JJ05<*85/&(/G(J+5/+58"(d%#%#$(5$(sorting-(@35<3(5$(83#(J+/A0#>(/G(*++*&'5&'(*(</00#<85/&(/G

#0#>#&8$(*<</+?5&'(8/(*($J#<5G5<(/+?#+1(=&?##?-(*$("/%($##(G+/>(83#(#c*>J0#$(/G(83#($#<85/&-(*G8#+(A%50?5&'(*

J+5/+58"(d%#%#(</&8*5&5&'(83#(#0#>#&8$(/G(*(</00#<85/&-(83#(#0#>#&8$(</>#(/%8(5&(83#($/+8#?(/+?#+(*$(83#"(*+#

+#>/H#?(G+/>(83#(d%#%#1(4#(@500(+#H5$58(835$(>#83/?(/G($/+85&'(5&(83#(&#c8($#<85/&(@35<3(5$(?#H/8#?(8/($/+85&'1

)+5/+58"(d%#%#$(*+#(%$#?(8/(5>J0#>#&8(J+5/+58"QA*$#?(+#$/%+<#($<3#?%05&'-(@3#+#(*(+#$/%+<#(5$($3*+#?(*>/&'

>*&"(<%$8/>#+$(@583(?5GG#+#&8(J+5/+585#$1(;3#(#>#+'#&<"(+//>(#c*>J0#('5H#&(5&(835$($#<85/&(5$(/&#($%<3(#c*>J0#1

F&/83#+(#c*>J0#(5$(7)Z($<3#?%05&'-(@3#+#(83#(7)Z(/G(*(</>J%8#+(5$($3*+#?(A"(>*&"(J+/<#$$#$(@583(?5GG#+#&8

J+5/+585#$-(*&?(83#(/J#+*85&'($"$8#>$(>*5&8*5&$(*(J+5/+58"(d%#%#(/G(*<85H#(J+/<#$$#$(@*585&'(8/(A#(#c#<%8#?1

)+5/+58"(d%#%#$(3*H#(>*&"(/83#+(*JJ05<*85/&$1(V/+(#c*>J0#-(*(J+5/+58"(d%#%#(%&?#+05#$(83#(G*>/%$(Dijkstra’s

algorithm-(*&(#GG5<5#&8(*0'/+583>(83*8(</>J%8#$($5&'0#Q$/%+<#($3/+8#$8(J*83$(5&(*('+*J3(*&?(3*$(>*?#(?5'58*0

&*H5'*85/&(*(+#*058"1(h*+5*&8$(/G(25D,$8+*m$(*0'/+583>(*+#(</+&#+($8/&#$(G/+(&*H5'*85/&$($"$8#>$($%<3(*$(q//'0#

S*J$-(*&?(83#(UJ#&(.3/+8#$8()*83(V5+$8(OU.)VR(J+/8/</0(G/+(+/%85&'(J*<,#8$(/&(83#(=&8#+&#81

)+5/+58"(p%#%#$(*+#(*0$/(%$#?(5&(Huffman codes(@35<3(*+#(%$#?(8/(</>J+#$$(S)I(*&?(6)bq(G50#$1

8.8. Sorting

./+85&'(5$(83#(J+/A0#>(/G(*++*&'5&'(*&(*++*"(/G(#0#>#&8$(*<</+?5&'(8/(*($J#<5G5#?(/+?#+1(=8(5$(/&#(/G(83#(>/$8

G%&?*>#&8*0(J+/A0#>$(5&(</>J%85&'(*&?(5$(5&3#+#&8(5&(>*&"(*JJ05<*85/&$-(8//(>*&"(8/(#&%>#+*8#1(=8(5$(*0$/(/&#(/G

83#(A#$8($8%?5#?(J+/A0#>$(5&(</>J%85&'-(*&?($/+85&'(*0'/+583>$(*A/%&?1(=&(835$($#<85/&-(@#(J+#$#&8($5c($/+85&'

*0'/+583>$1(4#(G5+$8(?#$<+5A#(83+##($5>J0#(*0'/+583>$(,&/@&(*$(Selection Sort-(Insertion Sort(*&?(Bubble Sort1

73*&<#$(*+#(83*8("/%(3*H#(5&*?H#+8#&80"(%$#?(*8(0#*$8(/&#(/G(83#>(@3#&("/%($/+8(*($>*00(</00#<85/&(/G(&%>A#+$1

4350#(83#"(*+#(5&8%585H#(*&?($8+*5'38G/+@*+?-(83#"(*+#(H#+"($0/@(@3#&(83#(</00#<85/&(8/($/+8(5$(0*+'#1(4#(83#&

?5$<%$$(83+##(#GG5<5#&8(*0'/+583>$(,&/@&(*$(Heap Sort-(Merge Sort(*&?(Quick Sort1(;3#$#(83+##(*0'/+583>$(*+#

>/+#($%A80#(*&?(<0#H#+(83*&(83#(*G/+#>#&85/&#?(/&#$-(*&?(*+#(H#+"(G*$8(#H#&(@3#&(83#(5&J%8(5$(0*+'#1

V/+($5>J05<58"(*&?(@583/%8(0/$$(/G('#&#+*058"-(@#(?#$<+5A#(*&?(?#>/&$8+*8#(*00(83#(*0'/+583>$(5&(835$($#<85/&(G/+

$/+85&'(*&(*++*"(/G(5&8#'#+$(5&(83#(*$<#&?5&'(/+?#+1(;3#(*0'/+583>$(#c8#&?(+#*?50"(G/+(*++*"$(/G(*&"('#&#+5<(8"J#

83*8(#583#+(5>J0#>#&8$(83#(7/>J*+*A0#(5&8#+G*<#-(/+(5$($%JJ05#?(@583(*(<%$8/>(</>J*+*8/+1(=&(?#$<+5A5&'(83#

*0'/+583>$(@#(*0$/(#&H5$5/&(83*8(83#(5&J%8(*++*"(5$(0*5?(/%8(3/+5a/&8*00"-(@583(83#(0/@(5&?#c(T(/&(83#(G*+(0#G8(#&?

*&?(83#(35'3(5&?#c-(@35<3(5$(83#(0#&'83(/G(83#(*++*"(>5&%$(C-(/&(83#(G*+(+5'38(#&?1

8.8.1. Naive Iterative Algorithms

Selection Sort

4/5/21, 10)50 PMIntermediate Programming

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%&$/+8#?($%A*++*"(A#</>#$(#>J8"1(;3#(G/00/@5&'(G5'%+#(G+/>(2*&5#0(N5*&'m$(8#c8A//,-(=&8+/?%<85/&(8/(6*H*

)+/'+*>>5&'(*&?(2*8*(.8+%<8%+#$-(500%$8+*8#$(#*<3(58#+*85/&(/G(83#(*0'/+583>(@3#&(83#(5&J%8(*++*"(5$(•E-(^-(L-(K-([-(C-

M€1(=&(83#(G5'%+#-(#*<3(05&#(+#J+#$#&8$(*&(58#+*85/&(/G(83#(*0'/+583>1(=&(#*<3(58#+*85/&-(83#(#0#>#&8$(</0/+#?(A0%#(/&

83#(0#G8(*+#(#0#>#&8$(/G(83#($/+8#?($%A*++*"-(@350#(83#(+#>*5&5&'(#0#>#&8$(8/(83#(+5'38(*+#(#0#>#&8$(/G(83#

%&$/+8#?($%A*++*"1

(

4/5/21, 10)50 PMIntermediate Programming

Page 159 of 185http://itec2150.gitlab.io/

;3#(G/00/@5&'(</?#(5>J0#>#&8$(.#0#<85/&(./+81

Insertion Sort

N5,#(.#0#<85/&(./+8-(=&$#+85/&(./+8(>*5&8*5&$(*($/+8#?($%A*++*"(/&(83#(0#G8(@35<3(5$(5&585*00"(#>J8"(*&?(#H#&8%*00"

</&$5$8$(/G(83#(#&85+#(*++*"(5&(83#($/+8#?(/+?#+-(*&?(*&(%&$/+8#?($%A*++*"(/&(83#(+5'38(@35<3(5&585*00"(</&$5$8$(/G

83#(#&85+#(5&J%8(*++*"(*&?(#H#&8%*00"(A#</>#$(#>J8"1(!/@#H#+-(%&05,#(5&(.#0#<85/&(./+8-(#0#>#&8$(/G(83#(%&$/+8#?

$%A*++*"(>*"(A#($>*00#+(83*&(#0#>#&8$(/G(83#($/+8#?($%A*++*"(?%+5&'(83#(#c#<%85/&(/G(=&$#+85/&(./+81(=&(#H#+"

58#+*85/&-(=&$#+85/&(./+8(5&$#+8$(83#(0#G8>/$8(#0#>#&8(/G(83#(%&$/+8#?($%A*++*"(5&8/(83#($/+8#?($%A*++*"(*8(83#

</++#<8(J/$585/&-(A"(</>J*+5&'(58(@583(*&?($35G85&'(#0#>#&8$(/G(83#($/+8#?(*++*"($8*+85&'(*8(83#(A*<,1(;3#(G/00/@5&'

G5'%+#(G+/>(2*&5#0(N5*&'m$(8#c8A//,-(=&8+/?%<85/&(8/(6*H*()+/'+*>>5&'(*&?(2*8*(.8+%<8%+#$-(500%$8+*8#$(#*<3

58#+*85/&(/G(83#(*0'/+583>(@3#&(83#(5&J%8(*++*"(5$(•E-(^-(L-(K-([-(C-(M€1(=&(83#(G5'%+#-(#*<3(05&#(+#J+#$#&8$(*&(58#+*85/&

/G(83#(*0'/+583>1(=&(#*<3(58#+*85/&-(83#(#0#>#&8$(</0/+#?(+#?(/&(83#(0#G8(*+#(#0#>#&8$(/G(83#($/+8#?($%A*++*"-(@350#

83#(+#>*5&5&'(#0#>#&8$(8/(83#(+5'38(*+#(#0#>#&8$(/G(83#(%&$/+8#?($%A*++*"1

publicpublic staticstatic voidvoid selectionSort(intint[] A) {

/**

* In each iteration, i is the index of the leftmost element

* of the unsorted subarray

forfor (intint i = 0; i < A.length - 1; i++) {

intint minIndex = i;

/**

* Find the index of the smallest element of the unsorted subarray

forfor (intint j = i + 1; j < A.length; j++) {

ifif (A[j] < A[minIndex]) {

minIndex = j;

}

/**

* Swap the leftmost element and the smallest element of the

* unsorted subarray

ifif (minIndex != i) {

swap(A, i, minIndex);

}

publicpublic staticstatic voidvoid swap(intint[] A, intint i, intint j) {

intint temp = A[i];

A[i] = A[j];

A[j] = temp;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 160 of 185http://itec2150.gitlab.io/

(

;3#(G/00/@5&'(</?#(5>J0#>#&8$(=&$#+85/&(./+81

4/5/21, 10)50 PMIntermediate Programming

Page 161 of 185http://itec2150.gitlab.io/

Selection Sort vs. Insertion Sort

4350#(.#0#<85/&(./+8(*&?(=&$#+85/&(./+8(*+#(A/83(H#+"($5>J0#(*&?(5&8%585H#-(=&$#+85/&(./+8(5$(%$%*00"(G*$8#+(83*&

.#0#<85/&(./+8(G/+(83#(G/00/@5&'(+#*$/&1(=&(#H#+"(J*$$(/G(=&$#+85/&($/+8-(83#(5&&#+(0//J(<*&($8/J(*$($//&(*$(58(G5&?$

83#(</++#<8(J/$585/&(G/+(83#(r<%++#&8r(#0#>#&8(8/(5&$#+8(5&8/(83#($/+8#?($%A*++*"1(=&(</&8+*$8-(5&(#H#+"(J*$$(/G

.#0#<85/&(./+8-(83#(5&&#+(0//J(>%$8(#c3*%$8(83#(#&85+#(%&$/+8#?($%A*++*"(8/(G5&?(83#(>5&5>%>1(=&(J*+85<%0*+-(@3#&

83#(5&J%8(*++*"(5$(&#*+0"($/+8#?-(=&$#+85/&(./+8(5$(*(0/8(G*$8#+(83*&(.#0#<85/&(./+81

Bubble Sort

publicpublic staticstatic voidvoid insertionSort(intint[] A) {

forfor (intint i = 1; i < A.length; i++) {

/**

* The current element to insert into the sorted subarray

intint current = A[i];

intint j = i - 1;

// Start at the back of the sorted subarray

/**

* Shift elements of the sorted subarray one position to the right

* until an element less than or equal to the current element is found

* or the beginning of the sorted subarray is passed

whilewhile (j >= 0 && A[j] > current) {

A[j+1] = A[j];

j--;

}

/**

* Insert the current element at the correct position

A[j+1] = current;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 162 of 185http://itec2150.gitlab.io/

`%AA0#(./+8(58#+*85H#0"($/+8$(*&(*++*"(A"(>*5&8*5&5&'(*&(%&$/+8#?($%A*++*"(/&(83#(0#G8(@35<3(5&585*00"(</&$5$8$(/G

83#(#&85+#(5&J%8(*++*"(*&?(#H#&8%*00"(A#</>#$(#>J8"-(*&?(*($/+8#?($%A*++*"(/&(83#(+5'38(@35<3(5$(5&585*00"(#>J8"

*&?(#H#&8%*00"(</&$5$8$(/G(83#(#&85+#(*++*"(5&(83#($/+8#?(/+?#+1(2%+5&'(83#(#c#<%85/&(/G(83#(*0'/+583>-(#H#+"

#0#>#&8(/G(83#(%&$/+8#?($%A*++*"(5$($>*00#+(83*&(/+(#d%*0(8/(#H#+"(#0#>#&8(/G(83#($/+8#?($%A*++*"1(=&(#H#+"(J*$$-

83#(*0'/+583>(>/H#$(83#(0*+'#$8(#0#>#&8(/G(83#(%&$/+8#?($%A*++*"(8/(83#(</++#<8(J/$585/&(A"(</>J*+5&'(*&?

$@*JJ5&'(*?D*<#&8(#0#>#&8$1(;3#(G/00/@5&'(G5'%+#(G+/>(2*&5#0(N5*&'m$(8#c8A//,-(=&8+/?%<85/&(8/(6*H*()+/'+*>>5&'

*&?(2*8*(.8+%<8%+#$-(500%$8+*8#$(#H#+"(J*$$(/G(83#(*0'/+583>(@3#&(83#(5&J%8(*++*"(5$(•E-(^-(L-(K-([-(C€1

q#&#+*05a5&'(83#(5?#*(5&(83#(#c*>J0#(*A/H#(+#$%08$(5&(*&(*0'/+583>(83*8($/+8$(*&(*++*"(5&(#c*<80"(&QC(J*$$#$-(@3#+#

&(5$(83#(0#&'83(/G(83#(*++*"1(;35$(3/@#H#+(</%0?(A#(@*$8#G%0(A#<*%$#(83#(*++*"(>*"(A#($/+8#?(5&(>%<3(G#@#+(J*$$#$1

V/+(#c*>J0#-(5G(83#(5&J%8(*++*"(5$(•M-(C-(E-(I-(K-(L€-(83#&(58(5$(#*$"(8/(<3#<,(83*8(83#(*++*"(@/%0?(A#($/+8#?(5&(D%$8(/&#

J*$$-(83#+#G/+#(83#(&#c8(J*$$#$(A#</>#(%&&#<#$$*+"1(4#(<*&(5>J+/H#(83#(*0'/+583>(A"($8/JJ5&'(58$(#c#<%85/&(D%$8

@3#&(83#(*++*"(5$($/+8#?-(%$5&'(83#(G/00/@5&'(5?#*1(=&(#*<3(J*$$-(@#(3*H#(83#(*0'/+583>(<3#<,(@3#83#+(*($@*J

/<<%+$(A#8@##&(*&"(J*5+(/G(*?D*<#&8(#0#>#&8$(/G(83#(%&$/+8#?($%A*++*"1(=G(&/($@*J(/<<%+$(?%+5&'(83#(#&85+#(J*$$-

83#&(83#(*++*"(5$(*0+#*?"($/+8#?-($/(83#(&#c8(J*$$#$(*+#(&/8(&##?#?1

;3#(G/00/@5&'(</?#(5>J0#>#&8$(`%AA0#(./+81

4/5/21, 10)50 PMIntermediate Programming

Page 163 of 185http://itec2150.gitlab.io/

8.8.2. Eﬃcient Algorithms

;3#(83+##($/+85&'(*0'/+583>$(?5$<%$$#?($/(G*+-(&*>#0"(.#0#<85/&(./+8-(=&$#+85/&(./+8(*&?(`%AA0#(./+8-(*+#(*00(H#+"

$5>J0#(*&?(/AH5/%$0"(</++#<81(;3#"(@/+,(G5&#(@3#&(83#(5&J%8(*++*"(5$($>*00(OG/+(#c*>J0#(@3#&(83#(0#&'83(/G(83#

5&J%8(*++*"(5$(5&(83#(/+?#+(/G(CT-TTT(/+(0#$$R1(!/@#H#+-(83#"(*+#(H#+"($0/@(@3#&(83#(5&J%8(*++*"(5$(0*+'#1(S/+#

J+#<5$#0"-(83#"(#*<3(3*H#(85>#(</>J0#c58"(UO&•ER1(9/%+(@500($8%?"(85>#(</>J0#c58"(/G(*0'/+583>$(*&?(83#(`5'(U

&/8*85/&(5&(=;b7(ICLTB(F?H*&<#?()+/'+*>>5&'1(l/%'30"($J#*,5&'-(835$(>#*&$(83*8(G/+($/+85&'(*&(*++*"(/G(0#&'83(&-

publicpublic staticstatic voidvoid bubbleSort(intint[] A) {

forfor (intint pass = 1; pass < A.length; pass++) {

booleanboolean noSwap = truetrue;

* i = 0 to A.length - pass are indices of the

* unsorted subarray

forfor (intint i = 0; i < A.length - pass; i++) {

/**

* If an element is larger than the next element, then

* swap them and set the noSwap flag to false

ifif (A[i] > A[i+1]) {

swap(A, i, i+1);

noSwap = falsefalse;

}

/**

* If no swap occurs during the entire pass, then the array is

* already sorted, so terminate the execution of the algorithm

ifif (noSwap) {

breakbreak;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 164 of 185http://itec2150.gitlab.io/

83#(&%>A#+(/G(/J#+*85/&$(#*<3(/G(83#(83+##(*0'/+583>$(%$#$(5&(83#(@/+$8(<*$#-(5$(J+/J/+85/&(8/(&•E1(V/+(#c*>J0#-(8/

$/+8(*&(*++*"(/G(CT(>5005/&(#0#>#&8$(O51#1(@3#&(&(](CT-TTT-TTT(](CT•WR-(.#0#<85/&(./+8-(=&$#+85/&(./+8(*&?(`%AA0#(./+8

#*<3(8*,#(*JJ+/c5>*8#0"(CT•CK(/J#+*85/&$(5&(83#(@/+$8(<*$#1(F(>/?#+&(</>>/?58"()7(#c#<%8#$(*A/%8(/&#(A5005/&

OCT•^R(/J#+*85/&$(J#+($#</&?1(;3#+#G/+#-(/&($%<3(*(J0*8G/+>-(58(8*,#$(#*<3(/G(83#(83+##(&*5H#(*0'/+583>$(*A/%8

CT•CK(P(CT•^(](CTT-TTT($#</&?$-(@35<3(5$(*A/%8(28 hours-(8/($/+8(*&(*++*"(/G(CT(>5005/&(#0#>#&8$1

=&(835$($%A$#<85/&-(@#(J+#$#&8(83+##(#GG5<5#&8($/+85&'(*0'/+583>$(Q(Heap Sort-(Merge Sort(*&?(Quick Sort-(@35<3

*+#(H#+"(G*$8(#H#&(@3#&(83#(5&J%8(5$(0*+'#1(S/+#(J+#<5$#0"-(83#"(#*<3(3*H#(85>#(</>J0#c58"(/&0"(UO&(0/'(&R-(@3#+#

83#(0/'*+583>(5$(/G(A*$#(E1(j/85<#(83*8(@350#(CT(>5005/&(>*"(A#(0*+'#-(83#(A*$#QE(0/'*+583>(/G(CT(>5005/&(5$(0#$$(83*&

EK-(@35<3(5$($>*00n(;3#+#G/+#-(8/($/+8(*&(*++*"(/G(CT(>5005/&(#0#>#&8$-(!#*J(./+8-(S#+'#(./+8(*&?(p%5<,(./+8(#*<3

8*,#(*A/%8(/&0"(E1K(s(CT•[(/J#+*85/&$-(*$(/JJ/$#?(8/(CT•CK(5&(83#(<*$#(/G(83#(83+##(&*5H#(*0'/+583>$1(U&(*(J0*8G/+>

83*8(#c#<%8#$(/&#(A5005/&(/J#+*85/&$(J#+($#</&?-(58(8*,#$(#*<3(/G(!#*J(./+8-(S#+'#(./+8(*&?(p%5<,(./+8(/&0"(*A/%8

0.3 second(8/($/+8(*&(*++*"(/G(CT(>5005/&(#0#>#&8$n

Heap Sort

F$(@#($*@(G+/>(83#($#<85/&(/&()+5/+58"(p%#%#$-(#H#+"(J+5/+58"(d%#%#('5H#$(+5$#(8/(*($/+85&'(*0'/+583>(*$(G/00/@$B

C1( 7/&$8+%<8(*(J+5/+58"(d%#%#(</&$5$85&'(/G(*00(#0#>#&8$(/G(83#(5&J%8(*++*"-(@3#+#(83#(J+5/+58"(5$(?#G5&#?(A"(#583#+

83#(&*8%+*0(/+?#+5&'(/G(83#(#0#>#&8$-(/+(83#(/+?#+5&'(5>J/$#?(A"(*(<%$8/>(</>J*+*8/+1

E1( l#>/H#(/&#(#0#>#&8(*8(*(85>#(G+/>(83#(J+5/+58"(d%#%#(%&850(58(5$(#>J8"1

`"(83#(J+5/+58"(d%#%#(J+/J#+8"-(83#(#0#>#&8$(*JJ#*+(5&(83#($/+8#?(/+?#+(*$(83#"(#c58(83#(d%#%#1(;35$(*0'/+583>(5$

,&/@&(*$(!#*J(./+8(@3#&(83#(J+5/+58"(d%#%#(5$(5>J0#>#&8#?(%$5&'(*(heap-(*(?*8*($8+%<8%+#(83*8("/%(@500(0#*+&(5&

=;b7(ICLTB(F?H*&<#?(J+/'+*>>5&'1(=&?##?-(*(6*H*(J+5/+58"(d%#%#(5$(3#*JQA*$#?1(;3#(G/00/@5&'(</?#(5>J0#>#&8$

!#*J(./+81

Merge Sort

publicpublic staticstatic voidvoid heapSort(Integer[] A) {

/**

* Construct a priority queue consisting of all elements of the

* input array. Using this constructor is more efficient than using

* the default constructor to create an empty priority queue and then

* adding each element of the array to the queue.

PriorityQueue<Integer> pq = newnew PriorityQueue<>(Arrays.asList(A));

/**

* Remove one element at a time from the priority queue and copy it

* to the array until the priority queue is empty.

forfor (intint i = 0; i < A.length; i++) {

A[i] = pq.remove();

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 165 of 185http://itec2150.gitlab.io/

S#+'#(./+8(5$(*&(#GG5<5#&8(*0'/+583>(83*8($/+8$(*&(*++*"(A"(recursion-(*(J/@#+G%0(8#<3&5d%#("/%(0#*+&#?(5&(73*J8#+

W1(=&(83#(A*$#(<*$#(@3#+#(83#(*++*"(5$(/G(0#&'83(/&#-(83#(*0'/+583>(?/#$(&/835&'-(*$(*($5&'0#8/&(5$($/+8#?1(=&('#&#+*0-

83#(*0'/+583>(?5H5?#$(83#(*++*"(5&8/(8@/(3*0H#$(Q(*(0#G8(3*0G(</&$5$85&'(/G(#0#>#&8$(G+/>(83#($8*+8(8/(83#(>5??0#

5&?#c(/G(83#(*++*"(*&?(*(+5'38(3*0G(</&$5$85&'(/G(83#(+#>*5&5&'(#0#>#&8$-(83#&(recursively($/+8$(83#(8@/(3*0H#$-(*&?

G5&*00"(>#+'#$(83#(8@/($/+8#?(3*0H#$(5&8/(*(@3/0#($/+8#?(*++*"1(;35$(5$(*&(5&$8*&<#(/G(*('#&#+*0(*0'/+583>(?#$5'&

J*+*?5'>(,&/@&(*$(divide-and-conquer1(;3#(G/00/@5&'(G5'%+#(G+/>(2*&5#0(N5*&'m$(8#c8A//,-(=&8+/?%<85/&(8/(6*H*

)+/'+*>>5&'(*&?(2*8*(.8+%<8%+#$-(500%$8+*8#$(83#(#c#<%85/&(/G(83#(*0'/+583>(@3#&(83#(5&J%8(*++*"(5$(•E-(^-(L-(K-([-(C-

M-(W€1

(

F$("/%(<*&($##-(83#(*<8%*0($/+85&'(3*JJ#&$(@3#&($%A*++*"$(*+#(>#+'#?1(;3#(G/00/@5&'(</?#(5>J0#>#&8$(S#+'#

./+8(*$(@#00(*$(83#(>#83/?(G/+(>#+'5&'(8@/($/+8#?(*++*"$(5&8/(*($5&'0#(/&#1

publicpublic staticstatic voidvoid mergeSort(intint[] A) {

/**

* Base Case: If the array is of length 1, then do nothing

ifif (A.length == 1) {

returnreturn;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 166 of 185http://itec2150.gitlab.io/

Quick Sort

intint n = A.length;

intint m = n / 2;

//Find the middle index of the array

/**

* Divide the array into two halves: left and right

intint[] left = newnew intint[m];

intint[] right = newnew intint[n-m];

forfor (intint i = 0; i < m; i++) {

left[i] = A[i];

}

forfor (intint i = 0; i < n-m; i++) {

right[i] = A[m+i];

}

/**

* Recursively sort the left and right halves

mergeSort(left);

mergeSort(right);

/**

* Merge the two sorted subarrays into a whole sorted array

merge(left, right, A);

}

/**

* Merges two sorted arrays into a single sorted array

* @param left a sorted array

* @param right another sorted array

* @param A the destination to store the merged array

publicpublic staticstatic voidvoid merge(intint[] left, intint[] right, intint[] A) {

intint curL = 0;

intint curR = 0;

intint cur = 0;

whilewhile (curL < left.length && curR < right.length) {

ifif (left[curL] < right[curR]) {

A[cur++] = left[curL++];

}

elseelse {

A[cur++] = right[curR++];

}

whilewhile (curL < left.length) {

A[cur++] = left[curL++];

}

whilewhile (curR < right.length) {

A[cur++] = right[curR++];

}

4/5/21, 10)50 PMIntermediate Programming

Page 167 of 185http://itec2150.gitlab.io/

p%5<,(./+8(5$(*&/83#+(#GG5<5#&8(?5H5?#Q*&?Q</&d%#+($/+85&'(*0'/+583>1(=&(83#(A*$#(<*$#(@3#+#(83#(*++*"(5$(/G(0#&'83

a#+/(/+(/&#-(83#+#(5$(&/835&'(8/(?/1(=&('#&#+*0-(83#(*0'/+583>(J5<,$(*(pivot(#0#>#&8(G+/>(83#(*++*"-(83#&(partitions

83#(*++*"(*+/%&?(J5H/8(5&8/(8@/($%A*++*"$(Q(*(0#G8($%A*++*"(@3#+#(#H#+"(#0#>#&8(5$(&/('+#*8#+(83*&(83#(J5H/8-(*&?(*

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83#(0#G8($%A*++*"(*&?(83#(+5'38($%A*++*"1(;3#(J5H/8(#0#>#&8(5$(%$%*00"(<3/$#&(+*&?/>0"(*>/&'(*00(*++*"(#0#>#&8$1

=8(5$(<0#*+(83*8(J*+8585/&5&'(83#(*++*"(*+/%&?(83#(J5H/8(5$(83#(#$$#&85*0(J*+8(/G(83#(*0'/+583>-(@3#+#($/+85&'(*<8%*00"

8*,#$(J0*<#1(F&(/AH5/%$(@*"(8/(5>J0#>#&8(83*8(5$(8/(<+#*8#(8@/(*%c505*+"(*++*"$(G/+(83#(0#G8(*&?(+5'38($%A*++*"$

+#$J#<85H#0"1(U&<#(83#(J5H/8(5$(<3/$#&-(/&#(<*&($5>J0"(58#+*8#(/H#+(83#(*++*"(*&?(</>J*+#(#*<3(#0#>#&8(@583(83#

J5H/81(=G(*&(#0#>#&8(5$($>*00#+(83*&(/+(#d%*0(8/(83#(J5H/8-(83#&(</J"(58(8/(83#(0#G8($%A*++*"e(/83#+@5$#(</J"(58(8/(83#

+5'38($%A*++*"1(=8(5$(3/@#H#+(@*$8#G%0(8/(<+#*8#(83#(#c8+*($J*<#(*&?(</J"(#0#>#&8$(A*<,(*&?(G/+83(A#8@##&(83#

/+5'5&*0(*&?(*%c505*+"(*++*"$(@3#&#H#+(@#(<*&(*H/5?(581(=8(8%+&$(/%8(83*8(J*+8585/&5&'(<*&(A#(?/&#(in place-(83*8(5$-

5&(83#(/+5'5&*0(*++*"(58$#0G(@583/%8(*&"(*%c505*+"(?*8*($8+%<8%+#-(*$(500%$8+*8#?(5&(83#(G/00/@5&'(G5'%+#(G+/>(2*&5#0

N5*&'m$(8#c8A//,-(=&8+/?%<85/&(8/(6*H*()+/'+*>>5&'(*&?(2*8*(.8+%<8%+#$-(G/+(83#(5&J%8(*++*"(•L-(E-(^-(I-([-(K-(T-(C-(M-

W€1

4/5/21, 10)50 PMIntermediate Programming

Page 168 of 185http://itec2150.gitlab.io/

(

4#(&/@(A+5#G0"(#cJ0*5&(83#(5&QJ0*<#(J*+8585/&(*0'/+583>1(;3#(500%$8+*85/&(*A/H#(*$$%>#$(83*8(83#(G5+$8(#0#>#&8(/G

83#(5&J%8(*++*"(5$(<3/$#&(*$(83#(J5H/81(=&('#&#+*0-(@3#&(83#(J5H/8(5$(&/8(83#(G5+$8(#0#>#&8-(/&#(<*&($@*J(58(@583(83#

G5+$8(#0#>#&8(*&?(83#&(J+/<##?(@583(83#($*>#(>#83/?1(;3#(*0'/+583>(>*5&8*5&$(8@/(J/5&8#+$-(*(0/@(J/5&8#+(83*8

$8*+8$(*8($#</&?(5&?#c(/G(83#(5&J%8(*++*"-(*&?(*(35'3(J/5&8#+(83*8(5$(5&585*00"(*8(83#(G*+Q+5'38(#&?(/G(83#(*++*"1(;3#

*0'/+583>(+#J#*8#?0"(*?H*&<#$(83#(0/@(J/5&8#+(8/(83#(+5'38(%&850(*&(#0#>#&8('+#*8#+(83*&(83#(J5H/8(5$(G/%&?-

*?H*&<#$(83#(35'3(J/5&8#+(8/(83#(0#G8(%&850(*&(#0#>#&8($>*00#+(83*&(/+(#d%*0(8/(83#(J5H/8(5$(G/%&?-(*&?($@*J$(83#

8@/(#0#>#&8$-(until the two pointers cross each other1(F8(835$(J/5&8-(*00(#0#>#&8$(8/(83#(0#G8(/G(83#(0/@(J/5&8#+(*+#

$>*00#+(83*&(/+(#d%*0(8/(83#(J5H/8-(@350#(*00(#0#>#&8$(8/(83#(+5'38(/G(83#(35'3(J/5&8#+(*+#('+#*8#+(83*&(83#(J5H/81(;3#

*0'/+583>(</>J0#8#$(83#(J*+8585/&(A"($@*JJ5&'(83#(J5H/8(@35<3(@*$(*8(83#(A#'5&&5&'(/G(83#(5&J%8(*++*"-(@583(83#

#0#>#&8(*8(83#(35'3(J/5&8#+(@35<3(5$(&/@(8/(83#(5>>#?5*8#(0#G8(/G(83#(0/@(J/5&8#+1(FG8#+(83#($@*J-(*00(#0#>#&8$(8/

83#(0#G8(/G(83#(J5H/8(*+#($>*00#+(83*&(/+(#d%*0(8/(83#(J5H/8-(*&?(*00(#0#>#&8$(8/(83#(+5'38(/G(83#(J5H/8(*+#('+#*8#+(83*&

83#(J5H/81(;3#(G/00/@5&'(</?#(5>J0#>#&8$(p%5<,(./+8(*$(@#00(*$(83#(J*+8585/&(>#83/?1

4/5/21, 10)50 PMIntermediate Programming

Page 169 of 185http://itec2150.gitlab.io/

publicpublic staticstatic voidvoid quickSort(intint[] A) {

quickSortHelper(A, 0, A.length, newnew Random());

}

/**

* The recursive helper method for Quick Sort that sorts in place a section of

* an array with a start index (inclusive) and an end index (exclusive)

* @param A an array

* @param start the start index of the section to sort

* @param end the end index of the section to sort

* @param rand the Random object for picking a pivot element

publicpublic staticstatic voidvoid quickSortHelper(intint[] A, intint start, intint end, Random rand) {

/**

* Base Case: If the array is of length 0 or 1, then do nothing

intint n = end - start;

ifif (n <= 1) {

returnreturn;

}

/**

* Pick a random index between start (inclusive) and end (exclusive),

* choose the element at this index as the pivot element, and

* swap the pivot with the element at start

intint pivotIdx = rand.nextInt(n) + start;

swap(A, start, pivotIdx);

/**

* Partition the section of A between start and end

* around the pivot

pivotIdx = partition(A, start, end);

/**

* Recursively sort the left subarray and the right subarray

quickSortHelper(A, start, pivotIdx, rand);

quickSortHelper(A, pivotIdx+1, end, rand);

}

/**

* Partitions the section of an array between a start index and an end index

* around a pivot element which is initially at the start index

* @param A an array

* @param start the start index of the section

* @param end the end index of the section

* @return the index of the pivot after the partition

publicpublic staticstatic intint partition(intint[] A, intint start, intint end) {

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 170 of 185http://itec2150.gitlab.io/

A Comparison of Heap Sort, Merge Sort and Quick Sort

`/83(!#*J(./+8(*&?(S#+'#(./+8(3*H#(@/+$8Q<*$#(85>#(</>J0#c58"(UO&(0/'(&R1(!/@#H#+-(?%#(8/(83#(</$8(8/(>*5&8*5&(*

3#*J-(!#*J(./+8(5$(%$%*00"($0/@#+(83*&(S#+'#(./+81

intint pivot = A[start];

intint low = start + 1;

intint high = end - 1;

/**

* Repeat until the low pointer and high pointer cross each other

whilewhile (low <= high) {

/**

* Advance the low pointer to the right until

* an element greater than the pivot is found

whilewhile (low <= high && A[low] <= pivot) {

low += 1;

}

/**

* Advance the high pointer to the left until an element

* smaller than or equal to the pivot is found

whilewhile (low <= high && A[high] > pivot) {

high -= 1;

}

/**

* Swap the elements at the low and high indices

ifif (low < high) {

swap(A, low++, high--);

}

/**

* Swap the pivot which was at the start index with

* the element at the high index. After the swap the

* partition is complete. The pivot is now at the

* high index. All elements in A[start], ..., A[high-1]

* are smaller than or equal to the pivot. All elements

* in A[high+1], ..., A[end-1] are greater than the pivot.

swap(A, start, high);

/**

* Return the high index which is now the pivot index

returnreturn high;

}

100

101

102

103

104

105

106

107

108

109

110

4/5/21, 10)50 PMIntermediate Programming

Page 171 of 185http://itec2150.gitlab.io/

=&(83#(@/+$8(<*$#-(p%5<,(./+8(</%0?(3*H#(85>#(</>J0#c58"(UO&•ER1(;35$(3*JJ#&$(@3#&(A*?(J5H/8(#0#>#&8$(*+#

<3/$#&(?%+5&'(83#(#c#<%85/&(/G(83#(*0'/+583>(83*8(+#$%08(5&(%&A*0*&<#?(J*+8585/&$1(F&(#c8+#>#(<*$#(5$(@3#+#(5&

#H#+"(+#<%+$5H#(<*00(83#(*0'/+583>(J5<,$(83#($>*00#$8(/+(83#(0*+'#$8(#0#>#&8(/G(*($%A*++*"(*$(83#(J5H/8-($/(83*8(*00

#0#>#&8$(/G(83#($%A*++*"(*JJ#*+(/&(/&#($5?#(/G(83#(J5H/8(*G8#+(83#(J*+8585/&1(.%<3(@/+$8Q<*$#($<#&*+5/$(*+#

3/@#H#+(#c8+#>#0"(%&05,#0"(5G(83#(J5H/8(5$(<3/$#&(randomly(*$(@#(?/(5&(/%+(5>J0#>#&8*85/&(*A/H#1(U&(*H#+*'#

*&?(5&(83#(/H#+@3#0>5&'(>*D/+58"(/G(*00(<*$#$-(p%5<,(./+8(3*$(85>#(</>J0#c58"(UO&(0/'(&R1(S/+#/H#+-(5&(J+*<85<#

Quick Sort is usually faster than Merge Sort-(*(J+5>*+"(+#*$/&(A#5&'(83*8(p%5<,(./+8(5$(in place1(=&(</&8+*$8-(S#+'#

./+8(&##?$(8/(*00/<*8#(*%c505*+"(>#>/+"($J*<#(*&?(</J"(#0#>#&8$(A#8@##&(83#(5&J%8(*&?(*%c505*+"($J*<#(8/(>#+'#

$/+8#?($%A*++*"$1(bH#&(/&(*(>/?#+&(</>J%8#+-(>#>/+"(/J#+*85/&$(*+#($8500($5'&5G5<*&80"($0/@#+(83*&(*+583>#85<

/J#+*85/&$1(43#&($J##?(5$(/%+(J+5>*+"(</&<#+&-(p%5<,(./+8(5$(%$%*00"(83#($/+85&'(*0'/+583>(/G(<3/5<#1

!/@#H#+-(S#+'#(./+8(3*$(*(&5<#(J+/J#+8"(,&/@&(*$(stability(83*8(>*,#$(58(?#$5+*A0#(G/+($/+85&'(complex objects1(F

$/+85&'(*0'/+583>(5$(stable(5G(58(+#$J#<8$(83#(/+?#+(/G(83#(#0#>#&8$(5&(83#(/+5'5&*0(5&J%8e(83*8(5$-(G/+(#0#>#&8$(/G(83#

same priority-(83#(*0'/+583>(preserves their order in the original input1(;35$(&/85/&(/G($8*A5058"(>*,#$(&/($#&$#(G/+

#0#>#&8$(/G(*(J+5>585H#(8"J#1(!/@#H#+-(58(5$(>#*&5&'G%0(@3#&(@#($/+8(/AD#<8$(/G(*(<0*$$1(4#(?#>/&$8+*8#(83#

>#*&5&'(*&?(%$#G%0&#$$(/G($8*A5058"(%$5&'(83#(#c*>J0#('5H#&(*8(835$($58#

O388J$BPP<*G#1#03*+/1</>PJ+/'+*>>5&'PD*H*QJ+/'+*>>5&'P@3"QD*H*Q%850Q*++*"$Q%$#$Q8@/Q$/+85&'Q*0'/+583>$PR1(7/&$5?#+(83#

G/00/@5&'(<0*$$(83*8(+#J+#$#&8$($8%?#&8$(8*,5&'(*(</%+$#(@583($#H#+*0($#<85/&$1

.%JJ/$#(83*8(@#(*+#('5H#&(*&(5&J%8(*++*"(/G(.8%?#&8(/AD#<8$(83*8(*+#(*0+#*?"($/+8#?(A"(&*>#-(*$(G/00/@$B

.%JJ/$#(83*8(&/@(@#($/+8(83#($8%?#&8$(A"($#<85/&1(FG8#+($/+85&'(83#('5H#&(*++*"(%$5&'(S#+'#(./+8(O/+(*&"($8*A0#

$/+85&'(*0'/+583>R-(83#(*++*"(A#</>#$

classclass Student {

String lastName;

String firstName;

intint section;

}

JAVA

John Alisson 2

Nabeel Aronowitz 3

Joe Jones 2

James Ledbetter 2

Ilya Lessing 1

Betty Lipschitz 2

Betty Neubacher 2

John Neubacher 3

Katie Senya 1

Jim Smith 3

Ping Yi 1

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 172 of 185http://itec2150.gitlab.io/

j/85<#(83*8(83#($8%?#&8$(*+#(&/8(/&0"($/+8#?(A"($#<85/&(Q($8%?#&8$(@5835&(#*<3($#<85/&(*+#(*0$/($/+8#?(A"(&*>#1(;35$

5$(A#<*%$#(J+5/+(8/(83#($/+85&'(A"($#<85/&-(83#($8%?#&8$(@#+#(*0+#*?"($/+8#?(A"(&*>#1(`#<*%$#(S#+'#(./+8(5$($8*A0#-

*$(58($/+8$(83#($8%?#&8$(A"($#<85/&-(58(J+#$#+H#$(83#(/+5'5&*0(/+?#+(OA"(&*>#R(/G(83#($8%?#&8$(@583(83#($*>#($#<85/&

&%>A#+1

=&(</&8+*$8-(p%5<,(./+8(5$(instable-(A#<*%$#(83#(5&QJ0*<#(J*+8585/&(*0'/+583>(5$(&/8(/+?#+(J+#$#+H5&'1(;3#(G/00/@5&'(5$

/&#(J/$$5A0#(/%8</>#(@3#&(@#(*JJ0"(p%5<,(./+8(8/($/+8(83#($*>#(5&J%8(A"($#<85/&B

;3#+#G/+#-(G/+($/+85&'(</>J0#c(/AD#<8$-(@3#&($8*A5058"(5$(+#d%5+#?-(S#+'#(./+8(5$(%$%*00"(83#(J+#G#++#?(*0'/+583>1

Arrays.sort, Collections.sort and Arrays.parallelSort

./+85&'(5$($/(G%&?*>#&8*0(83*8(#H#+"(>/?#+&(J+/'+*>>5&'(0*&'%*'#(J+/H5?#$(#GG5<5#&8('#&#+5<(>#83/?$(/+

G%&<85/&$(G/+($/+85&'(5&(83#5+(F)=$1(6*H*(J+/H5?#$(8@/($%<3(>#83/?$(Q(Arrays.sort(G/+($/+85&'(*++*"$-(*&?

Collections.sort(G/+($/+85&'(05$8$1(F00(83#(?#8*50$(/G(83#(8@/(>#83/?$(<*&(A#(G/%&?(3#+#

O388J$BPP?/<$1/+*<0#1</>PD*H*$#P[P?/<$P*J5PD*H*P%850PF++*"$138>0R(*&?(3#+#

O388J$BPP?/<$1/+*<0#1</>PD*H*$#P[P?/<$P*J5PD*H*P%850P7/00#<85/&$138>0R1(43#&($/+85&'(*(05$8-(7/00#<85/&$1$/+8(G5+$8(</J5#$(83#(05$8

#0#>#&8$(8/(*&(*++*"-(83#&($/+8$(83#(*++*"(%$5&'(F++*"$1$/+8-(*&?(G5&*00"(</J5#$(83#(#0#>#&8$(G+/>(83#($/+8#?(*++*"

A*<,(8/(83#(05$81(`#0/@(@#(#0*A/+*8#(/&(F++*"$1$/+81

Ilya Lessing 1

Katie Senya 1

Ping Yi 1

John Alisson 2

Joe Jones 2

James Ledbetter 2

Betty Lipschitz 2

Betty Neubacher 2

Nabeel Aronowitz 3

John Neubacher 3

Jim Smith 3

JAVA

Ilya Lessing 1

Ping Yi 1

Katie Senya 1

Betty Lipschitz 2

Betty Neubacher 2

Joe Jones 2

James Ledbetter 2

John Alisson 2

John Neubacher 3

Jim Smith 3

Nabeel Aronowitz 3

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 173 of 185http://itec2150.gitlab.io/

F++*"$1$/+8(5$(?#G5&#?(G/+(*++*"$(/G(*00(J+5>585H#(8"J#$(@583(*(&*8%+*0(/+?#+5&'(O*00(&%>#+5<*0(8"J#$(*&?(<3*+*<8#+$R-

*$(@#00(*$(*++*"$(/G(/AD#<8$1(V/+($/+85&'(/AD#<8$-(F++*"$1$/+8(*JJ05#$(8/(#H#+"(<0*$$(83*8(5>J0#>#&8$(83#(7/>J*+*A0#

5&8#+G*<#-(*&?(*&(*+A58+*+"(<0*$$(@3#&($%JJ05#?(@583(*(<%$8/>(</>J*+*8/+(G/+(83#(<0*$$1(V/+(#c*>J0#-(5G(F(5$(*&

*++*"(/G(/AD#<8$(/G(*(<0*$$(7(83*8(5>J0#>#&8$(7/>J*+*A0#-(83#&

$/+8$(F(*<</+?5&'(8/(83#(/+?#+5&'(?#G5&#?(A"(83#(compareTo(>#83/?(/G(70*$$(71

=G(F(5$(*&(*++*"(/G(/AD#<8$(/G(*&(*+A58+*+"(<0*$$(*&?(<>J(5$(*(<%$8/>(</>J*+*8/+(?#G5&#?(G/+(83#(<0*$$-(83#&

$/+8$(F(*<</+?5&'(8/(83#(/+?#+5&'($J#<5G5#?(A"(83#(</>J*+*8/+(<>J1

F++*"$1$/+8(#>J0/"$(two($/+85&'(*0'/+583>$(Q(58(%$#$(*(G*$8(H#+$5/&(/G(Quick Sort(,&/@&(*$(Dual Pivot Quicksort(8/

$/+8(J+5>585H#$-(*&?(%$#$(*(G*$8(H*+5*&8(/G(Merge Sort(,&/@&(*$(Timsort(8/($/+8(/AD#<8$1

4#(G5&*00"(>#&85/&(83*8(5&(6*H*([(*&/83#+($/+85&'(>#83/?-(Arrays.parallelSort-(@*$(5&8+/?%<#?(@35<3(5>J+/H#$

83#(J#+G/+>*&<#(/G(F++*"$1$/+8(A"(multithreading-(*(8/J5<("/%(@500(0#*+&(5&(=;b7(ICLTB(F?H*&<#?()+/'+*>>5&'1

8.9. Exercises

8.9.1. Exercise 1

9/%(*+#(not(*00/@#?(8/(%$#(83#(Collections.reverse(>#83/?(G/+(835$(#c#+<5$#1

O*R(4+58#(*('#&#+5<(>#83/?

83*8(+#H#+$#$(83#(/+?#+(/G(83#(#0#>#&8$(/G(*('5H#&(*++*"(05$8(in place-(83*8(5$-(5&(83#(/+5'5&*0(05$8(58$#0G(@583/%8(%$5&'

*&"(*%c505*+"(?*8*($8+%<8%+#1(.5&<#(83#(5&J%8(05$8(5$(*&(array(05$8-(58(5$(efficient(8/(*<<#$$(58$(#0#>#&8$(A"(5&?#c1(V/+(835$

>#83/?-("/%(*+#(*00/@#?(8/(58#+*8#(/H#+(83#(5&J%8(05$8(A"(5&?#c-(*&?(%$#(83#(get(*&?(set(>#83/?$(/G(83#(05$8(8/(+#*?

*&?(>/?5G"(83#(#0#>#&8(*8(*&"(5&?#c1

OAR(4+58#(*('#&#+5<(>#83/?

83*8(/&(5&J%8(*(05&,#?(05$8-(+#8%+&$(*&/83#+(05&,#?(05$8(83*8(</&8*5&$(83#(#0#>#&8$(/G(83#(/+5'5&*0(05$8(5&(83#(+#H#+$#

/+?#+1(.5&<#(83#(5&J%8(05$8(5$(*(linked(05$8-(58(5$(inefficient(8/(*<<#$$(58$(#0#>#&8$(A"(5&?#c1(V/+(835$(>#83/?-("/%(*+#(not

*00/@#?(8/(*<<#$$(83#(#0#>#&8$(/G(83#(5&J%8(05$8(A"(5&?#c1(=&$8#*?-("/%(must(%$#(83#(58#+*8/+(/G(83#(5&J%8(05$8(8/

Arrays.sort(A)

JAVA

Arrays.sort(A, cmp)

JAVA

publicpublic staticstatic <E> voidvoid reverseArrayListInPlace(ArrayList<E> list)

JAVA

publicpublic staticstatic <E> LinkedList<E> reverseLinkedList(LinkedList<E> list)

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 174 of 185http://itec2150.gitlab.io/

58#+*8#(/H#+(83#(05$8(D%$8(/&<#(5&(#583#+(?5+#<85/&-(*&?(#&(+/%8#(*??(#*<3(#0#>#&8(8/(*&(/%8J%8(05$8(%$5&'(*(J+/J#+

add(>#83/?1

O<R(4+58#(*('#&#+5<(>#83/?

83*8(+#H#+$#$(83#(/+?#+(/G(83#(#0#>#&8$(/G(*('5H#&(05&,#?(05$8(in place1(F$(5&()*+8(OAR-("/%(*+#(not(*00/@#?(8/(*<<#$$

83#(#0#>#&8$(/G(83#(5&J%8(05$8(A"(5&?#c1(=&$8#*?-("/%(must(58#+*8#(/H#+(83#(05$8(D%$8(/&<#(%$5&'(58$(05$8(58#+*8/+1(OHintB

Z$#(8@/(58#+*8/+$-(/&#($8*+85&'(*8(83#(3#*?(*&?(83#(/83#+($8*+85&'(*8(83#(8*50(/G(83#(5&J%8(05$81R

8.9.2. Exercise 2

=>J0#>#&8(83#(G/00/@5&'('#&#+5<(>#83/?$(using the list iterator(s) of the input list(s)1(V/+(#*<3(>#83/?(5&H/0H5&'(*&

5&?#c-($8*+8(83#(58#+*8/+(*8(83#(#&?(/G(83#(05$8(83*8(5$(<0/$#+(8/(83#(5&?#c1

O*R

;35$(>#83/?(*??$(83#('5H#&(#0#>#&8(8/(83#('5H#&(05$8(*8(83#($J#<5G5#?(5&?#c1(;3#(>#83/?($3/%0?(83+/@(*&

IndexOutOfBoundException(5G(83#($J#<5G5#?(5&?#c(5$(/%8(/G(+*&'#-(51#1(5G(O5&?#c(x(T(~~(5&?#c(y(05$81$5a#ORR1(9/%(*+#

not(*00/@#?(8/(%$#(83#(addO5&8(5&?#c-(b(#R(>#83/?(/G(83#(5&J%8(05$81

OAR

;35$(>#83/?(+#>/H#$(83#(#0#>#&8(*8(83#($J#<5G5#?(5&?#c(G+/>(83#('5H#&(05$81(;3#(>#83/?($3/%0?(83+/@(*&

IndexOutOfBoundException(5G(83#($J#<5G5#?(5&?#c(5$(/%8(/G(+*&'#-(51#1(5G(O5&?#c(x(T(~~(5&?#c(y](05$81$5a#ORR1(9/%(*+#

not(*00/@#?(8/(%$#(83#(removeO5&8(5&?#cR(>#83/?(/G(83#(5&J%8(05$81

O<R

;35$(>#83/?(+#8%+&$(83#(#0#>#&8(/G(83#('5H#&(05$8(*8(83#($J#<5G5#?(5&?#c1(;3#(>#83/?($3/%0?(83+/@(*&

IndexOutOfBoundException(5G(83#($J#<5G5#?(5&?#c(5$(/%8(/G(+*&'#-(51#1(5G(O5&?#c(x(T(~~(5&?#c(y](05$81$5a#ORR1(9/%(*+#

not(*00/@#?(8/(%$#(83#(getO5&8(5&?#cR(>#83/?(/G(83#(5&J%8(05$81

O?R

publicpublic staticstatic <E> LinkedList<E> reverseLinkedList(LinkedList<E> list)

JAVA

publicpublic staticstatic <E> voidvoid add(List<E> list, intint index, E element)

JAVA

publicpublic staticstatic <E> E remove(List<E> list, intint index)

JAVA

publicpublic staticstatic <E> E get(List<E> list, intint index)

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 175 of 185http://itec2150.gitlab.io/

;35$(>#83/?(+#J0*<#$(83#(#0#>#&8(/G(83#('5H#&(05$8(*8(83#($J#<5G5#?(5&?#c(@583(83#('5H#&(#0#>#&81(;3#(>#83/?

$3/%0?(83+/@(*&(IndexOutOfBoundException(5G(83#($J#<5G5#?(5&?#c(5$(/%8(/G(+*&'#-(51#1(5G(O5&?#c(x(T(~~(5&?#c(y]

05$81$5a#ORR1(9/%(*+#(not(*00/@#?(8/(%$#(83#(setO5&8(5&?#c-(b(#0#>#&8R(>#83/?(/G(83#(5&J%8(05$81

O#R

;35$(>#83/?(+#8%+&$(83#(5&?#c(/G(83#(G5+$8(/<<%++#&<#(/G(83#($J#<5G5#?(#0#>#&8(5&(83#('5H#&(05$8(5G(83#(#0#>#&8(5$(5&

83#(05$8-(*&?(QC(/83#+@5$#1(9/%(*+#(not(*00/@#?(8/(%$#(83#(indexOfOUAD#<8(/R(>#83/?(/G(83#(5&J%8(05$81

OGR

;35$(>#83/?(+#8%+&$(83#(5&?#c(/G(83#(0*$8(/<<%++#&<#(/G(83#($J#<5G5#?(#0#>#&8(5&(83#('5H#&(05$8(5G(83#(#0#>#&8(5$(5&

83#(05$8-(*&?(QC(/83#+@5$#1(9/%(*+#(not(*00/@#?(8/(%$#(83#(lastIndexOfOUAD#<8(/R(>#83/?(/G(83#(5&J%8(05$81

O'R

;35$(>#83/?(+#>/H#$(83#(G5+$8(/<<%++#&<#(/G(83#($J#<5G5#?(#0#>#&8(G+/>(83#('5H#&(05$8-(5G(83#(#0#>#&8(#c5$8$1(;3#

>#83/?(+#8%+&$(8+%#(5G(83#($J#<5G5#?(#0#>#&8(5$(J+#$#&8(5&(83#(05$8-(*&?(G*0$#(/83#+@5$#1(9/%(*+#(not(*00/@#?(8/(%$#

83#(removeOUAD#<8(/R(>#83/?(/G(83#(5&J%8(05$81

O3R

;35$(>#83/?(+#8%+&$(8+%#(5G(83#(8@/('5H#&(05$8(</&8*5&$(83#($*>#(#0#>#&8$(5&(83#($*>#(/+?#+1(9/%(*+#(not(*00/@#?

8/(%$#(83#(equalsOUAD#<8(/R(>#83/?(/G(#583#+(5&J%8(05$81

8.9.3. Exercise 3

4#(>#&85/&#?(83*8(*($8*<,(5$(*(H#+"($J#<5*0(05$8(@583(/&#(#&?(<0/$#?1(=&(835$(#c#+<5$#("/%(*+#(8/(5>J0#>#&8(*($8*<,

%$5&'(*(linked list1(7+#*8#(*(J%A05<('#&#+5<(<0*$$(MyStackxEy1(;3#(<0*$$($3/%0?(3*H#(*(A*<,5&'(05&,#?(05$8(*$(*

J+5H*8#(5&$8*&<#(H*+5*A0#B

publicpublic staticstatic <E> voidvoid set(List<E> list, intint index, E element)

JAVA

publicpublic staticstatic <E> intint indexOf(List<E> list, E element)

JAVA

publicpublic staticstatic <E> intint lastIndexOf(List<E> list, E element)

JAVA

publicpublic staticstatic <E> booleanboolean remove(List<E> list, E element)

JAVA

publicpublic staticstatic <E> booleanboolean equals(List<E> list1, List<E> list2)

JAVA

privateprivate LinkedList<E> backingList;

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 176 of 185http://itec2150.gitlab.io/

;3#(A*<,5&'(05$8(%&?#+05#$(83#($8*<,("/%(*+#(*A/%8(8/(5>J0#>#&81(9/%(<*&(%$#(#583#+(#&?(/G(83#(A*<,5&'(05$8(*$(83#

8/J(/G(83#($8*<,1

=>J0#>#&8(83#(G/00/@5&'(>#83/?$(G/+(83#(MyStackxEy(<0*$$-(%$5&'(83#(J+/J#+(>#83/?$(/G(83#(A*<,5&'(05$8B

F(</&$8+%<8/+(83*8(8*,#$(&/(J*+*>#8#+(*&?(<+#*8#$(*(&#@-(#>J8"($8*<,1

public void pushOE(#R1(;35$(>#83/?(*??$(83#($J#<5G5#?(#0#>#&8(8/(83#(8/J(/G(83#($8*<,1

public E popOE(#R1(;35$(>#83/?(+#>/H#$(*&?(+#8%+&$(83#(#0#>#&8(*8(83#(8/J(/G(83#($8*<,1(=8(83+/@$(*&

EmptyStackException(5G(83#($8*<,(5$(#>J8"1

public E peekOE(#R1(;35$(>#83/?(+#8%+&$(83#(#0#>#&8(*8(83#(8/J(/G(83#($8*<,(@583/%8(+#>/H5&'(581(=8(83+/@$(*&

EmptyStackException(5G(83#($8*<,(5$(#>J8"1

bc<#J8(@3#&(<3#<,5&'(G/+(*&(#>J8"($8*<,-(83#(push-(pop(*&?(peek(>#83/?$($3/%0?(only(%$#(83#(addFirst-

removeFirst(*&?(getFirst(>#83/?$-(/+(83#(addLast-(removeLast(*&?(getLast(>#83/?$(/G(83#(A*<,5&'(05$8-

?#J#&?5&'(/&(@35<3(#&?(/G(83#(05$8("/%(%$#(*$(83#(8/J(/G(83#($8*<,1

8.9.4. Exercise 4

4#(>#&85/&#?(83*8(*(d%#%#(5$(*0$/(*(H#+"($J#<5*0(05$8(@3#+#(#0#>#&8$(*+#(/&0"(*??(*8(/&#(#&?(*&?(+#>/H#?(*8(83#

/83#+(#&?(/G(83#(05$81(=&(835$(#c#+<5$#("/%(*+#(8/(5>J0#>#&8(*(d%#%#(%$5&'(*(linked list1(7+#*8#(*(J%A05<('#&#+5<(<0*$$

MyQueuexEy1(;3#(<0*$$($3/%0?(3*H#(*(A*<,5&'(05&,#?(05$8(*$(*(J+5H*8#(5&$8*&<#(H*+5*A0#B

;3#(A*<,5&'(05$8(%&?#+05#$(83#(d%#%#("/%(*+#(*A/%8(8/(5>J0#>#&81

=>J0#>#&8(83#(G/00/@5&'(>#83/?$(G/+(83#(MyQueuexEy(<0*$$-(%$5&'(83#(J+/J#+(>#83/?$(/G(83#(A*<,5&'(05$8B

F(</&$8+%<8/+(83*8(8*,#$(&/(J*+*>#8#+(*&?(<+#*8#$(*(&#@-(#>J8"(d%#%#1

public void addOE(#R1(;35$(>#83/?(*??$(83#($J#<5G5#?(#0#>#&8(8/(83#(tail(/G(83#(d%#%#1

public E removeOR1(;35$(>#83/?(+#>/H#$(*&?(+#8%+&$(83#(#0#>#&8(*8(83#(head(/G(83#(d%#%#1(=8(83+/@$(*

NoSuchElementException(5G(83#(d%#%#(5$(#>J8"1

public E peekHeadOR1(;35$(>#83/?(+#8%+&$(83#(#0#>#&8(*8(83#(head(/G(83#(d%#%#(@583/%8(+#>/H5&'(581(=8(83+/@$

*(NoSuchElementException(5G(83#(d%#%#(5$(#>J8"1

public E peekTailOR1(;35$(>#83/?(+#8%+&$(83#(#0#>#&8(*8(83#(tail(/G(83#(d%#%#(@583/%8(+#>/H5&'(581(=8(83+/@$(*

NoSuchElementException(5G(83#(d%#%#(5$(#>J8"1

bc<#J8(@3#&(<3#<,5&'(G/+(*&(#>J8"(d%#%#-(83#(add-(remove-(peakHead(*&?(peakTail(>#83/?$($3/%0?(only(%$#

83#(>#83/?$(G/+(*<<#$$5&'(83#(8@/(#&?$(/G(83#(A*<,5&'(05$81

8.9.5. Exercise 5

privateprivate LinkedList<E> backingList;

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 177 of 185http://itec2150.gitlab.io/

=&(835$(#c#+<5$#-("/%(*+#(8/($/0H#(H*+5*&8(/G(83#(A*0*&<#?(J*+#&83#$#$(J+/A0#>(@583(83+##(?5GG#+#&8(8"J#$(/G

J*+#&83#$#$-(@3#+#(oOo-(oRo-(o•o-(o€o-(ozo(*&?(o}o(</%0?(*00(A#(J+#$#&8(5&(83#(5&J%81(.%<3(*($#d%#&<#(/G(J*+#&83#$#$(5$

A*0*&<#?(5G(#H#+"(/J#&(J*+#&83#$5$(5$(<0/$#?(A"(*(<0/$5&'(J*+#&83#$5$(/G(83#(same type(*&?(#H#+"(<0/$5&'

J*+#&83#$5$(<0/$#$(*&(/J#&5&'(J*+#&83#$5$(/G(83#(same type(5&(83#(correct order1(V/+(#c*>J0#-(rzO•€R}r(*&?(rOR•€z}r

*+#(A*0*&<#?-(@3#+#*$(rO€r(*&?(r•O€Rr(*+#(&/8(A*0*&<#?1

Z$5&'(*(stack-(@+58#(*(>#83/?

83*8(/&(*&(5&J%8($8+5&'(</&$5$85&'(/G(oOo-(oRo-(o•o-(o€o-(ozo(*&?(o}o-(?#<5?#$(@3#83#+(/+(&/8(83#(5&J%8(5$(*(A*0*&<#?($#d%#&<#

/G(J*+#&83#$#$1

8.9.6. Exercise 6

Z$5&'(*(priority queue-(@+58#(*('#&#+5<(>#83/?

83*8(/&(5&J%8(*(05$8(F(/G(/AD#<8$(/G(83#('#&#+5<(<0*$$(E-(*&(5&8#'#+(,(x(F1$5a#OR-(*&?(*(</>J*+*8/+(<>J(/&(83#(<0*$$(E-

+#8%+&$(*(05$8(</&$5$85&'(/G(83#(,($>*00#$8(#0#>#&8$(5&(83#(/+?#+(83*8(5$(?#G5&#?(A"(<>J1(9/%(*+#(8/(@+58#(83#(>#83/?

G/00/@5&'(83#($8#J$(A#0/@B

C1( 7+#*8#(*(J+5/+58"(d%#%#(G/+(/AD#<8$(/G(83#('#&#+5<(<0*$$(E-(%$5&'(83#('5H#&(</>J*+*8/+(<>J1

E1( F??(*00(#0#>#&8$(/G(83#(5&J%8(05$8(F(8/(83#(J+5/+58"(d%#%#1

I1( 7*00(*(J+/J#+(>#83/?(8/(+#>/H#(G+/>(83#(J+5/+58"(d%#%#(,(85>#$1(b*<3(85>#(*&(#0#>#&8(5$(+#>/H#?(G+/>(83#

J+5/+58"(d%#%#-(*??(58(8/(*&(/%8J%8(05$81

K1( l#8%+&(83#(/%8J%8(05$81

8.9.7. Exercise 7

;3#(Point(<0*$$(?#G5&#?(A#0/@(+#J+#$#&8$(J/5&8$(5&(*(8@/Q?5>#&$5/&*0(J0*&#1

publicpublic staticstatic booleanboolean isBalanced2(String parentheses)

JAVA

publicpublic staticstatic <E> List<E> kSmallest(List<E> A, intint k, Comparator<E> cmp)

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 178 of 185http://itec2150.gitlab.io/

!#+#(83#(x(*&?(y(5&$8*&<#(H*+5*A0#$(+#J+#$#&8(83#(x(*&?(yQ<//+?5&*8#$(/G(*(J/5&8(5&(83#(J0*&#1

4+58#(*('#&#+5<(>#83/?

83*8(/&(5&J%8(*(05$8(F(/G(J/5&8$(*&?(*&(5&8#'#+(,(x(F1$5a#OR-(+#8%+&$(*(05$8(</&$5$85&'(/G(83#(,(<0/$#$8(J/5&8$(8/(83#

/+5'5&(OT-(TR1

HintB

C1( 2#G5&#(*(</>J*+*8/+(G/+(83#(Point(<0*$$(83*8('5H#$(35'3#+(J+5/+585#$(8/(J/5&8$(<0/$#+(8/(83#(/+5'5&1

E1( 7*00(83#(>#83/?(kSmallest(G+/>(83#(J+#H5/%$(#c#+<5$#1

8.9.8. Exercise 8

V/+(8@/(&%>A#+$(c(*&?("-(@#(?#G5&#(83#5+(distance(8/(A#(~c(Q("~-(51#1(83#(*A$/0%8#(H*0%#(/G(83#(?5GG#+#&<#(A#8@##&(c

*&?("1(=&(835$(#c#+<5$#-("/%(*+#(8/(@+58#(8@/(?5GG#+#&8(>#83/?$(8/($/0H#(83#(G/00/@5&'(J+/A0#>B(q5H#&(*&(*++*"(/G

5&8#'#+$-(G5&?(83#(?5$8*&<#(A#8@##&(83#(closest pair(/G(#0#>#&8$-(51#1(G5&?(83#(minimum distance(*>/&'(*00(J*5+$(/G

#0#>#&8$(5&(83#(*++*"1(V/+(#c*>J0#-(5G(83#(5&J%8(*++*"(5$(•[-(CE-(C^-(I-(CL€-(83#&("/%+(>#83/?$($3/%0?(+#8%+&(I-

A#<*%$#(83#(<0/$#$8(J*5+(/G(#0#>#&8$(5&(83#(*++*"(5$(•CE-(CL€(*&?(83#5+(?5$8*&<#(5$(~CE(Q(CL~(](I1

O*R(4+58#(*(>#83/?

83*8(G5&?$(83#(minimum distance(*>/&'(*00(J*5+$(/G(#0#>#&8$(5&(83#(5&J%8(*++*"(F-(A"(exhaustively searching for the

minimum through all pairs of elements using a nested loop1

publicpublic classclass Point {

privateprivate doubledouble x;

privateprivate doubledouble y;

publicpublic Point(doubledouble x, doubledouble y) {

thisthis.x = x;

thisthis.y = y;

}

publicpublic doubledouble getX() {

returnreturn x;

}

publicpublic doubledouble getY() {

returnreturn y;

}

JAVA

publicpublic staticstatic List<Point> kClosestToOrigin(List<Point> A, intint k)

JAVA

publicpublic staticstatic intint closestPairBruteForce(intint[] A)

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 179 of 185http://itec2150.gitlab.io/

OAR(=&(835$(J*+8-("/%(*+#(8/(@+58#(*(>%<3(>/+#(#GG5<5#&8(>#83/?(G/+($/0H5&'(83#($*>#(J+/A0#>(83*&(83#(A+%8#QG/+<#

>#83/?("/%(@+/8#(5&()*+8(O*R1(4+58#(*(>#83/?

83*8(G5&?$(83#(minimum distance(*>/&'(*00(J*5+$(/G(#0#>#&8$(5&(83#(5&J%8(*++*"(F-(A"(first sorting(83#(5&J%8(*++*"

%$5&'(Arrays.sort(/+(Arrays.parallelSort-(83#&(G5&?5&'(83#(>5&5>%>(?5$8*&<#(*>/&'(/&0"(83#(adjacent pairs(/G

#0#>#&8$(5&(83#(sorted(*++*"1

O<R(4+58#(*(>*5&(>#83/?(8/(8#$8(*&?(</>J*+#("/%+(</?#(G/+(closestPairBruteForce(*&?(closestPairSort-(*$

G/00/@$B

V5+$8('#&#+*8#(*($>*00(O$*"(/G(0#&'83(CTR(*++*"(/G(random(5&8#'#+$-(<*00(A/83(>#83/?$(/&(83#($*>#(5&J%8(*++*"

*&?(A#($%+#(83*8(83#"(A/83('5H#(83#($*>#(</++#<8(*&$@#+1(l#J#*8(835$($#H#+*0(85>#$1

j/@(8+"(83#(G/00/@5&'(5&J%8($5a#$B(CTTT-(CT-TTT-(CTT-TTT(*&?(CTTT-TTT1(V/+(#*<3(5&J%8($5a#-('#&#+*8#(*&(*++*"(/G

83*8($5a#(</&$5$85&'(/G(random(5&8#'#+$-(<*00(A/83(>#83/?$(/&(83#($*>#(5&J%8(*++*"(*&?(time your methods1

l#J#*8(835$($#H#+*0(85>#$(G/+(#*<3(5&J%8($5a#1(43*8(?/("/%(/A$#+H#\(=G("/%+(5>J0#>#&8*85/&$(*+#(</++#<8-("/%

$3/%0?(/A$#+H#(83*8(closestPairSort(5$(>%<3(G*$8#+(closestPairBruteForce(*$(83#(5&J%8($5a#(5&<+#*$#$1(7*&("/%

#cJ0*5&(835$(J3#&/>#&/&-(%$5&'(time complexity(83*8(5$(A+5#G0"(?5$<%$$#?(5&(835$(<3*J8#+\

8.9.9. Exercise 9

=>J0#>#&8(*(generic(H#+$5/&(/G(.#0#<85/&(./+8-(=&$#+85/&(./+8-(`%AA0#(./+8-(!#*J(./+8-(S#+'#(./+8(*&?(p%5<,(./+8

G/+($/+85&'(*&(*++*"(/G(/AD#<8$(G+/>(*(generic class that implements(Comparable1(;3#(3#*?#+$(/G(83#(>#83/?$

$3/%0?(A#(*$(G/00/@$B

publicpublic staticstatic intint closestPairSort(intint[] A)

JAVA

publicpublic staticstatic <T extendsextends Comparable<? supersuper T>> voidvoid selectionSort(T[] A)

JAVA

publicpublic staticstatic <T extendsextends Comparable<? supersuper T>> voidvoid insertionSort(T[] A)

JAVA

publicpublic staticstatic <T extendsextends Comparable<? supersuper T>> voidvoid bubbleSort(T[] A)

JAVA

publicpublic staticstatic <T extendsextends Comparable<? supersuper T>> voidvoid heapSort(T[] A)

JAVA

publicpublic staticstatic <T extendsextends Comparable<? supersuper T>> voidvoid mergeSort(T[] A)

JAVA

publicpublic staticstatic <T extendsextends Comparable<? supersuper T>> voidvoid quickSort(T[] A)

JAVA

4/5/21, 10)50 PMIntermediate Programming

Page 180 of 185http://itec2150.gitlab.io/

F0$/(@+58#(*(>*5&(>#83/?(8/(8#$8(83#(*A/H#($5c(>#83/?$(*$(G/00/@$1(7+#*8#(*($>*00(*++*"(/G($8+5&'$(/+(/AD#<8$(G+/>

*&"(<0*$$(83*8(5>J0#>#&8$(7/>J*+*A0#1(7*00(#*<3(/G(83#($5c(>#83/?$(*A/H#-(*$(@#00(*$(Arrays.sort(/+

Arrays.parallelSort-(8/($/+8(83#($*>#(5&J%8(*++*"(*&?(H#+5G"(83*8(83#"(*00('5H#(83#(</++#<8(+#$%081

8.9.10. Exercise 10

O*R(=>J0#>#&8(*(generic(H#+$5/&(/G(.#0#<85/&(./+8-(=&$#+85/&(./+8-(`%AA0#(./+8-(!#*J(./+8-(S#+'#(./+8(*&?(p%5<,

./+8(G/+($/+85&'(*&(*++*"(/G(/AD#<8$(G+/>(*(generic class when supplied with a custom(comparator1(;3#(3#*?#+$(/G

83#(>#83/?$($3/%0?(A#(*$(G/00/@$B

;3#(J*+8$(A#0/@(*+#(G/+(8#$85&'(*&?(</>J*+5&'("/%+(>#83/?$(5&()*+8(O*R1

OAR(7+#*8#(83#(G/00/@5&'(<0*$$(83*8(+#J+#$#&8$($8%?#&8$(8*,5&'(*(</%+$#(@583($#H#+*0($#<85/&$B

4+58#(*(</&$8+%<8/+(*&?(*(8/.8+5&'(>#83/?(G/+(83#(<0*$$1

2#G5&#(*(</>J*+*8/+(cmp(G/+(83#(Student(<0*$$(83*8(/+?#+$($8%?#&8$(G5+$8(A"(0*$8(&*>#(5&(*0J3*A#85<(/+?#+-(83#&(A"

G5+$8(&*>#(5&(*0J3*A#85<(/+?#+(@3#&(8@/($8%?#&8$(3*H#(83#($*>#(0*$8(&*>#1

O<R(4+58#(*(>*5&(>#83/?(8/(8#$8("/%+(>#83/?$(G+/>()*+8(O*R(*$(G/00/@$1

7+#*8#(*&(*++*"(</&$5$85&'(/G(83#(G/00/@5&'(.8%?#&8(/AD#<8$(5&(83#('5H#&(/+?#+B

publicpublic staticstatic <T> voidvoid selectSort(T[] A, Comparator<T> cmp)

JAVA

publicpublic staticstatic <T> voidvoid insertionSort(T[] A, Comparator<T> cmp)

JAVA

publicpublic staticstatic <T> voidvoid bubbleSort(T[] A, Comparator<T> cmp)

JAVA

publicpublic staticstatic <T> voidvoid heapSort(T[] A, Comparator<T> cmp)

JAVA

publicpublic staticstatic <T> voidvoid mergeSort(T[] A, Comparator<T> cmp)

JAVA

publicpublic staticstatic <T> voidvoid quickSort(T[] A, Comparator<T> cmp)

JAVA

classclass Student {

String lastName;

String firstName;

intint section;

}

JAVA

4/5/21, 10)50 PMIntermediate Programming

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7*00(#*<3(/G(83#($5c(>#83/?$(G+/>()*+8(O*R-(*$(@#00(*$(Arrays.sort(/+(Arrays.parallelSort-(8/($/+8(83#(*++*"(%$5&'

83#(</>J*+*8/+(cmp(G+/>()*+8(OAR1(F00(83#($#H#&(>#83/?$($3/%0?('5H#

*$(83#(/%8</>#1

O?R(2#G5&#(*&/83#+(</>J*+*8/+(cmp2(83*8(/+?#+$(.8%?#&8(/AD#<8$(A"($#<85/&(5&(*$<#&?5&'(/+?#+1(=&(83#(>*5&

>#83/?(<*00(#*<3(/G(83#($5c(>#83/?$(G+/>()*+8(O*R-(*$(@#00(*$(Arrays.sort(/+(Arrays.parallelSort-(8/($/+8(83#

+#$%085&'(*++*"(G+/>()*+8(O<R-(835$(85>#(%$5&'(cmp2(*$(83#(</>J*+*8/+1(7/>J*+#(83#(+#$%08$(/G(83#($#H#&(>#83/?$1

43*8(?/("/%(/A$#+H#\(435<3(>#83/?$(*+#($8*A0#\

8.10. Issue Tracker/Comments

=$$%#(;+*<,#+ O388J$BPP'583%A1</>P3J*+,WP3#0JY?#$,P5$$%#$R

John Neubacher 3

Ilya Lessing 1

Nabeel Aronowitz 3

Joe Jones 2

Katie Senya 1

John Alisson 2

Betty Neubacher 2

James Ledbetter 2

Betty Lipschitz 2

Ping Yi 1

Jim Smith 3

JAVA

John Alisson 2

Nabeel Aronowitz 3

Joe Jones 2

James Ledbetter 2

Ilya Lessing 1

Betty Lipschitz 2

Betty Neubacher 2

John Neubacher 3

Katie Senya 1

Jim Smith 3

Ping Yi 1

JAVA

4/5/21, 10)50 PMIntermediate Programming

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9. Glossary

Behavior

*<85/&$(/G(*&(/AD#<8e(+#J+#$#&8#?(A"(83#(>#83/?$(/G(*&(/AD#<81

Class

*(A0%#J+5&8(83*8(?#G5&#$(*&(/AD#<81

Heap memory

?"&*>5<*00"(*00/<*8#?(>#>/+"(%$#?(8/($8/+#(/AD#<8$1

Object

+#J+#$#&8$(*&(#&858"(5&(83#(+#*0(@/+0?(*&?(3*$($8*8#(*&?(A#3*H5/+e(*&(5&$8*&<#(/G(*(<0*$$1

Object-oriented programming

*(@*"(/G(/+'*&5a5&'(</?#(*+/%&?(/AD#<8$-(5&$8#*?(/G(*<85/&$1

Reference

>#>/+"(*??+#$$(/G(@3#+#(83#(/AD#<8(5$(0/<*8#?1

Reference type

*(<0*$$e(H*+5*A0#(/G(835$(8"J#(<*&(+#G#+#&<#(*&(/AD#<8(/G(*(<0*$$1

Reference variable

H*+5*A0#(/G(*(<0*$$(8"J#-(@35<3(</&8*5&$(*(+#G#+#&<#(8/(83#(/AD#<8(/G(83*8(<0*$$1

Stack memory

$8/+#$(0/<*0(H*+5*A0#$(/G(J+5>585H#(8"J#(*&?(+#G#+#&<#(H*+5*A0#$e(>#>/+"(5$(*<<#$$#?(5&(V5+$8(=&(N*$8(U%8(/+?#+1

State

+#J+#$#&8#?(A"(?*8*(G5#0?$(/+(*88+5A%8#$(/G(83#(/AD#<81

Association

*('#&#+*0(A5&*+"(+#0*85/&(A#8@##&(8@/($#J*+*8#(<0*$$#$1(V/+(#c*>J0#-(*($8%?#&8(8*,5&'(*(</%+$#(5$(*&(*$$/<5*85/&

A#8@##&(83#(.8%?#&8(<0*$$(*&?(83#(7/%+$#(<0*$$1

Aggregation

*&(*$$/<5*85/&(@3#&(/&#(/AD#<8(%$#$(*&/83#+(/AD#<81

Composition

*&(*$$/<5*85/&(@3#&(/&#(/AD#<8(/@&$(/83#+(<0*$$(*&?(/83#+(<0*$$(<*&&/8(>#*&5&'G%00"(#c5$81(7/>J/$585/&(5$

$8+/&'#+(83*&(*''+#'*85/&1

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Overriding method

43#&(*(>#83/?(5&(*($%A<0*$$(3*$(83#($*>#(&*>#-($*>#(J*+*>#8#+$(/+($5'&*8%+#-(*&?($*>#(+#8%+&(8"J#$O/+($%AQ

8"J#R(*$(*(>#83/?(5&(58$($%J#+<0*$$1

Overloading method

*(<0*$$(5$(*00/@#?(8/(3*H#(>/+#(83*&(/&#(>#83/?(3*H5&'(83#($*>#(&*>#(*$(0/&'(*$(83#5+(J*+*>#8#+(05$8$(*+#

?5GG#+#&81

Inheritance

*(>#<3*&5$>(8/(?#G5&#(&#@(<0*$$#$(G+/>(#c5$85&'(<0*$$#$1(=&(D*H*-(<0*$$#$(<*&(5&3#+58(83#(J+/J#+85#$(*&?(>#83/?$

/G($%J#+<0*$$1

Superclass

*('#&#+*0(<0*$$(@35<3(*(>#83/?O$R(8/(*($%A<0*$$1(U+(83#(<0*$$(A#5&'(5&3#+58#?(G+/>1

Subclass

;3#(?#+5H#?(<0*$$(83*8(5$(?#+5H#?(G+/>($%J#+<0*$$1

Exception

F&(#++/&#/%$(/+(*&/>*0/%$(</&?585/&(83*8(</>#$(%J(@3#&(*(J+/'+*>(5$(+%&&5&'1

Exception Handling

F&(*JJ+/*<3(83*8($#J*+*8#$(*(J+/'+*>m$(&/+>*0(</?#(G+/>(58m$(#++/+Q3*&?05&'(</?#1

Throw

;/(83+/@(*&(#c<#J85/&(5$(8/(<+#*8#(*&(#c<#J85/&(/AD#<8(*&?(J*$$(58(/GG(8/(83#(+%&Q85>#(#&H5+/&>#&81(;35$(5$(?/&#

#cJ05<58"(5&(</?#(%$5&'(83#(throw(,#"@/+?1

Stack Trace

F($8*<,(8+*<#(5$($/>#85>#$(<*00#?(*($8*<,(A*<,8+*<#(/+(#H#&(D%$8(*(A*<,8+*<#1(;3#($8*<,(8+*<#5$(*(05$8(/G($8*<,

G+*>#$1(F($8*<,(G+*>#(5&?5<*8#$(*(>/>#&8(?%+5&'(*&(*JJ05<*85/&m$(#c#<%85/&(@3#&(*(>#83/?(5$(<*00#?1(F($8*<,

G+*>#(</&8*5&$(5&G/+>*85/&(*A/%8(@3#+#(83#(>#83/?(@*$(<*00#?(G+/>(5&(83#(6*H*($/%+<#(</?#1(./(83#(6*H*($8*<,

8+*<#('#&#+*8#?(@3#&(*&(#c<#J85/&(5$(<*00#?(5$(*(05$8(/G(G+*>#$(83*8($8*+8$(*8(05&#(5&(83#(>#83/?(83#(#c<#J85/&

/<<%++#?(*&?(#c8#&?$(A*<,(8/(@3#&(83#(J+/'+*>($8*+8#?1

File

F(+#$/%+<#(%$#?(8/($8/+#(*(</00#<85/&(/G(?*8*(/&(*(</>J%8#+($8/+*'#(?#H5<#1

Text File

F(</>J%8#+(G50#(</&$5$85&'(/G(3%>*&(+#*?*A0#(Z&5</?#(<3*+*<8#+$1(;"J5<*00"(+#*?(%$5&'(*(8#c8(#?58/+(05,#(83#(/&#

5&(>/$8(=2bm$1(7/&$5?#+#?(3%>*&(+#*?*A0#1

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Binary File

F(</>J%8#+(G50#($8/+#?(5&(83#(&*85H#(A5&*+"(</?#(/G(83#(</>J%8#+1(j/8(</&$5?#+#?(3%>*&(+#*?*A0#1

Input

=&G/+>*85/&(/+(?*8*(G+/>(*&(#c8#+&*0($/%+<#(+#*?(5&8/(*(6*H*(J+/'+*>1

Output

=&G/+>*85/&(/+(?*8*(G+/>(*(6*H*(J+/'+*>(@+588#&(8/(*&(#c8#+&*0($/%+<#1

Open a File

7+#*8#(*($8+#*>(/G(?*8*(8/(/+(G+/>(*(</>J%8#+(G50#1

File Stream

F(/&#(@*"(d%#%#(/G(?*8*(#583#+(8/(/+(G+/>(*(G50#1(;3#(/+?#+(/G(?*8*(5&(83#(d%#%#(+#J+#$#&8$(83#(/+?#+(/G(83#(?*8*

5&(83#(G50#1

Close a File

V0%$3(*&?(<0/$#(*($8+#*>(/G(?*8*(8/(/+(G+/>(*(G50#1(43#&(@+585&'(*(G50#-(G/+<#$(83#(J+/'+*>(8/(@*58(%&850(*00(?*8*(5&

83#($8+#*>(3*$(A##&(@+588#&(8/(83#(G50#1(43#&(+#*?5&'(*(G50#-(8#+>5&*8#$(*&"(G%+83#+(?*8*(</>5&'(G+/>(83#(G50#1

Delimiter

2#05>58#+$(*+#(@358#$J*<#(<3*+*<8#+$(%$#?(8/($#J*+*8#(H*+5/%$(J5#<#$(/G(?*8*(5&(*(8#c8(G50#1(bc*>J0#$(*+#(*(A0*&,

$J*<#-(8*A-(/+(#&?(/G(05&#(<3*+*<8#+$(@35<3(?/(&/8($3/@(%J(*$(J+5&8(5&(*(8#c8(G50#1

bounded type

F('#&#+5<(8"J#(A#5&'($J#<5G5#?(*$(*($%A8"J#(/G(*&/83#+(8"J#

upper bounded wildcard (<? extends E>)

A/%&?$(@583(%JJ#+(5&3#+58*&<#(</&$8+*5&8(A"(%$5&'(#8#&?$(,#"@/+?1

lower bound wildcard (<? super E>)

A/%&?$(5$(%$5&'(83#(@50?<*+?(<3*+*<8#+(O\R-(G/00/@5&'(A"(83#($%J#+(,#"@/+?(A"(58$(0/@#+(A/%&?1

unbounded wildcard(<?>)

A/%&?$(@35<3(5$($J#<5G5#?(%$5&'(x\y1(835$(5$(<*00#?(%&,&/@&(8"J#1

raw type

*(&*>#(/G(*('#&#+5<(<0*$$(/+(5&8#+G*<#(@583/%8(*&"(8"J#(*+'%>#&8$1

type erasure

83#(J+/<#$$(/G(8"J#(<3#<,5&'(/&0"(*8(</>J50#(85>#(*&?(?5$<*+?5&'(83#(#0#>#&8(8"J#(5&G/+>*85/&(*8(+%&85>#1

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recursion

</>J%8*85/&(83*8(5&H/H0#$(*(G%&<85/&(O/+(>#83/?R(<*005&'(58$#0G

base case

83#($5>J0#$8(<*$#(5&(*(+#<%+$5H#($/0%85/&

recursive case

>5++/+$(83#(/H#+*00($/0%85/&(A%8(@583($5>J05G5#?(5&J%8(H*0%#$

direct recursion

@3#&(83#($*>#(>#83/?(<*00$(58$#0G

indirect recursion

@3#&(>/+#(83*&(/&#(>#83/?(5$(5&H/0H#?(5&(*(+#<%+$5/&

recursive backtracking

@3#&(+#<%+$5/&(5$(%$#?(8/(A%50?(*($#8(/G(<*&?5?*8#($/0%85/&$(*&?(*(<+58#+5*(5$(*JJ05#?(8/($#0#<8(83#(+5'38(/&#$