, SOLUTION MANUAL FOR Object-Oriented Data Structures Using Java
Fourth Edition Dale
Important Notes
The file includes the complete test bank, organized chapter by chapter.
A sample of selected pages has been provided for preview.
All available appendices and Excel files (if included in the original resources) are
provided.
Quizzes, Midterm and final exams are included (if available in the original resources).
We continuously update our files to ensure you receive the latest and most accurate
editions.
New editions are added regularly – stay connected for updates!
⚠️Note on Answer Keys: If the answer key is not included within the chapter
questions, you will find the complete answers and solutions at the end of each
chapter.
✅ Why Buy From Us?
📚 Complete & organized chapter-by-chapter – no missing content, no guessing.
⚡ Instant digital delivery – get your file the moment you pay, no waiting.
📅 Always up to date – we track new editions so you always get the latest version.
💬 Friendly support – real humans ready to help, anytime you need us.
🔒 Safe & secure – thousands of satisfied students trust us every semester.
🛡️Our Guarantees
💰 Money-Back Guarantee: Not satisfied? We offer a full refund – no questions asked.
🔄 Wrong File? No Problem: Contact us and we will replace it immediately with the
correct version, free of charge.
⏰ 24/7 Support: We are always here – reach out anytime and expect a fast response.
,Object-Oriented Data Structures using Java, 4th Edition
Selected Answers to Chapter 1 Exercises
Dale/Joyce/Weems
February, 2016
This file contains answers to exercises from the end of Chapter 1 of the 4th Edition of Object Oriented Data
Structures using Java. This file is intended for use only by instructors who have adopted the textbook.
Please do not post these answers on the internet. All instructors should be aware that it is possible that these
answers will be made public through carelessness or mischievous intent.
Note that we include answers for most, but not all of the exercises. We do not include answers if the
question is just a matter of opinion or of personal experience. In such cases we simply state that “answers
will vary”. Sometimes an exercise is really a “drill” rather than a question, so we don’t answer it. We do
not provide answers for major coding projects, although we may provide guidelines. Sometimes we do not
provide answers for medium sized coding projects, although we hope to provide all of these eventually
(check back later; or even better, send us your suggested solution and we will include it and give you credit
if it is appropriate). Finally, in cases where the answer to a question is found easily in the body of the text
we sometimes indicate the page number where the answer can be found, rather than repeating the
information here. The intent of such questions is for the students to describe the information in their own
words.
Chapter One – Getting Organized
Many of the questions in this chapter’s exercises are “thought questions.” The answers given here are
typical or suggested responses, but they are not the only possible answers.
Section 1 – Classes, Objects, and Applications
1. Many of the winners’ contributions dealt with programming, starting with Perlis in 1966, Dijkstra in
1972, and Knuth in 1974. But the list goes on. The winners whose work dealt primarily with object-
orientation are Wirth in 1984, Ole-Johan Dahl and Kristen Nygaard in 2001 and Kay in 2003.
2. See http://www.omg.org/gettingstarted/what_is_uml.htm#12DiagramTypes.
3. A class defines a structure or template for an object or a set of objects. An object is an instance of a
class. An example is a blueprint of a building and the building itself. Another example, from the text, of
a Java class/object is the Date class and the myDate, yourDate, ourDate objects.
4. See pages 5 and 6.
5. According to the program, the number of days between 1/1/1900 and 1/1/2000 is 36524.
Clearly there are 24 leap years.
According to the program, the number of days between 1/1/2000 and 1/1/2100 is 36525.
So that represents 25 leap years.
The difference is because 1900, being divisible by 100 is not a leap year, whereas 2000, even though it
is divisible by 100, is still a leap year because it is divisible by 400.
6. a. Answers will vary.
b. Answers will vary.
c. The number of days between11/21/1783 and 7/20/1969 is 67811
9. There are many possible “correct” answers for each part of this question. The intent was not for the
student to create code, but rather just identify a good set of variables and methods. Here are sample
,Chapter 1 / Getting Organized Page 2
answers for parts a and b:
a. Time Counter
instance variables: protected int totalMinutes;
protected int counter;
methods: public void addTime(int minutes, int seconds);
public void addTime(int minutes);
public int getTotalTime();
public int getAvgTime();
b. Basketball Statistics
instance variables: protected int score;
protected int fieldGoalsAttempted;
protected int fieldGoalsMade;
protected int freeThrowsAttempted;
protected int freeThrowsMade;
methods: public void fieldGoalMissed();
public void freeThrowMissed();
public void fieldGoalMade(int value); // value indicates 2 or 3 point shot
public void freeThrowMade();
public int getScore();
public float fieldGoalPercentage();
public float freeThrowPercentage();
Section 2 – Organizing Classes
14. See pages 12 – 16.
15. a. AbstractList
b. 3
c. 31
d. 16
e. AbstractCollection
16.
a. Legal - getDay is a public method that returns an int
b. Legal- getYear is a public method that returns an int
c. Illegal - increment is not defined for Date objects
d. Legal - increment is defined for IncDate objects
e. Legal - object variables can be assigned to objects of the same class
f. Legal - subclasses are assignment compatible with the superclasses above them in the class
hierarchy
g. Illegal - superclasses are not assignment compatible with the subclasses below them in the class
hierarchy
19. See pages19 – 21.
20. a. 15 plus 2 in support.cards
b. 5
c. i. java.io, java.util, ch05.collections, support
ii. It uses the wild card character to import all needed classes from the first three packages but it
explicitly imports the FamousPerson class from the support package
d. i. It depends on the compiler whether a syntax error is generated but in any case other classes will not
,Chapter 1 / Getting Organized Page 3
be able to import and use the class.
ii. Most compliers will simply compile the class although depending on settings you may receive a
warning.
iii. You get a syntax error since the compiler cannot locate the needed Date class.
21.
a. Yes
b. Labels
c. Length
d. records
e. media
Section 3 – Exceptional Situations
22. See page 27.
Section 4 – Data Structures
26. Answers will vary.
27. In order of occurrence:
alphabetized list of buttons sorted list
wall map two dimensional array
connections of trains linked list
ticket line queue
direct access to car 4 direct access to an array location
walking through train cars traversing a linked list
tray holder stack
Pez dispenser stack
candy machine button accessing an array
28. Answers will vary.
29.
a. Nodes are airports; edges connect airports that have flights available between them
b. Nodes are countries; edges connect countries that border each other
c. Nodes are research articles; directed edges connect articles to the articles that they reference
d. Nodes are actors; edges connect actors to the actors they have appeared in the same movies as them
e. Nodes are the computers; edges show a direct network link between the two computers
f. Nodes are rooms; edges are between rooms which have a connecting tunnel
g. Nodes are web pages; directed edges represent a hyperlink from the first page to the second
Section 5 – Basic Structuring Mechanisms
30. a.
address word
...
099
100 3
101 'c' | 'a' | 't' |
... …
123 10
124 20
...
str1: 135 100
,Chapter 1 / Getting Organized Page 4
136
b.
address word
...
099
100 3
101 'c' | 'a' | 't' |
... …
123 10
124 10
...
str1: 135 100
str2: 136 100
31. See pages 35-36
32. The output of the code would be
5/5/2000
5/5/2000
5/6/2000
5/6/2000
33. See page 36.
34. The output of the code would be
not equal
equal
equal
35. A program that meets the specifications is
//----------------------------------------------------------------------
// Exer35.java by Dale/Joyce/Weems Chapter 1
//
// Solves Chapter 1, Exercise 35
//----------------------------------------------------------------------
public class Exer35
{
public static void main(String[] args)
{
int[] squares = new int[10];
for (int i = 0; i < 10; i++)
squares[i] = i * i;
for (int i = 0; i < 10; i++)
,Chapter 1 / Getting Organized Page 5
System.out.println(squares[i]);
}
}
36. A program that meets the specifications is
//----------------------------------------------------------------------
// Exer36.java by Dale/Joyce/Weems Chapter 1
//
// Solves Chapter 1, Exercise 36
//----------------------------------------------------------------------
public class Exer36
{
public static void main(String[] args)
{
Date[] dates = new Date[10];
int month, day, year;
for (int i = 0; i < 10; i++)
dates[i] = new Date(12, i+1, 2005);
for (int i = 0; i < 10; i++)
System.out.println(dates[i]);
}
}
This solution assumes that the Date class is “visible” to the Exer36 application.
Section 7 – Comparing Algorithms: Big-O Analysis
39. Best Case: all answers are 1 – just need to be very lucky
Worst Case:
Sequential Binary
a. 10 10 4
b. 1,000 1,000 10
c. 1,000,000 1,000,000 20
d. 1,000,000,000 1,000,000,00030
40. Answers can vary. The important thing is that the student's answer is clear, and consistent.
41. The answer to the last part of the questions is:
a. approximately 1.37
b. approximately 8.87
c. 4
d. approximately 5.5
42.
a. O(N2)
b. O(N2)
c. O(N5)
d. O(N2)
e. O(N4)
f. O(N2)
,Chapter 1 / Getting Organized Page 6
43.
a. O(N)
b. O(N2)
c. O(log2N)
d. O(1)
e. O(N)
f. O(N)
44. The order of growth is O(N). A O(1) approach can be created based on the formula for the sum of the
integers between 1 … N being N (N + 1) / 2.
45.
a. O(1)
b. O(N)
c. O(N) ... even though on average takes N/2 steps, that is still O(N)
46. 27 15 83 12 104 28 57 30
12 15 83 27 104 28 57 30
12 15 83 27 104 28 57 30
12 15 27 83 104 28 57 30
12 15 27 28 104 83 57 30
12 15 27 28 30 83 57 104
12 15 27 28 30 57 83 104
12 15 27 28 30 57 83 104
End of Selected Answers to Chapter 1 Exercises
,Object-Oriented Data Structures using Java, 4th Edition
Selected Answers to Chapter 2 Exercises
Dale/Joyce/Weems
February, 2016
This file contains answers to exercises from the end of Chapter 2 of the 4th Edition of Object Oriented Data
Structures using Java. This file is intended for use only by instructors who have adopted the textbook.
Please do not post these answers on the internet. All instructors should be aware that it is possible that these
answers will be made public through carelessness or mischievous intent.
Note that we include answers for most, but not all of the exercises. We do not include answers if the
question is just a matter of opinion or of personal experience. In such cases we simply state that “answers
will vary”. Sometimes an exercise is really a “drill” rather than a question, so we don’t answer it. We do
not provide answers for major coding projects, although we may provide guidelines. Sometimes we do not
provide answers for medium sized coding projects, although we hope to provide all of these eventually
(check back later; or even better, send us your suggested solution and we will include it and give you credit
if it is appropriate). Finally, in cases where the answer to a question is found easily in the body of the text
we sometimes indicate the page number where the answer can be found, rather than repeating the
information here. The intent of such questions is for the students to describe the information in their own
words.
Chapter Two – The Stack ADT
Section 1 – Abstraction
1. Answers will vary but might include things such as driving a car using the car’s “interface” and without
knowing anything about how the engine works.
2.
a. Application level (e.g., College of Engineering’s enrollment information for 1988)
b. Abstract level (e.g., list of student academic records)
c. Implementation level (e.g., array of objects that contain the variables studentID (an integer),
lastName (a string of characters), firstName (a string of characters), etc.)
3. The efficiency of the operations.
4. An abstract method is a method declared in a class or an interface without a method body.
5. This should cause a compile time error – the compiler should not create Java bytecode for the
SampleClass. Error messages might vary across compilers. On my system I received two error
messages, both very much to the point:
SampleClass is not abstract and does not override abstract method
sampleMethod() in SampleInterface
sampleMethod() in SampleClass cannot implement sampleMethod() in
SampleInterface; attempting to use incompatible return type
6.
a. False Interfaces are not instantiated.
b. True An interface specifies some implementation requirements for a class.
c. False Only interfaces extend interfaces.
d. True Just so it also includes all of the methods listed in the interface.
e. False It must include methods for each method listed in the interface - they can be abstract
methods however.
f. False You can only instantiate objects of a concrete class.
, Chapter 2 / The Stack ADT Page 2
7. From our point of view the precondition and the described exception are redundant. The precondition
states that the number parameter will be greater than zero. So, there is no need to check for that
condition. If we need to check for that condition then it should not be stated as a pre-condition.
8. You cannot instantiate an interface like you instantiate a class to create an object. Interfaces are
typically used to define requirements for a class. You can define a class that implements an interface
and then instantiate objects of that class.
9. These answers will be similar to the implementations of Circle and Rectangle provided in the
text, except of course they must use appropriate formulas for perimeter and area.
Section 2 – The Stack
12.
a. false
b. true
c. true
d. false
e. true
f. false
g. false
h. false – not if the stack is empty
i. true
j. true
k. false
13. The classic operation both returns and removes the top element of the stack, whereas our pop operation
only removes the top element. Its return type is void.
14 a. 7 5 1
b. 2 1 3 4
c. 1 1 1 1
15.
a. Imagine placing the places the friend visited, in sequential order, onto a stack and then repeatedly
visit the place at the top of the stack, and pop it, essentially retracing their steps in reverse order
until
you find the umbrella.
b. As each higher and higher bid is made place it on a stack. Retraction of the highest bid amounts to
popping the bid off the stack.
Section 3 – Collection Elements
16. See pages 81-84.
17. The code is very straightforward.
Section 4 – Formal Specification
18. a. The stack will act as a LIFO structure.
b. A stack class will provide the operations push, pop, top, isEmpty, and isFull with the
signatures provided in the interface and functionality as described in the comments.
c. A stack object will throw exceptions if pop or top are invoked on an empty stack or if push is
invoked on a full stack.
19. An application programmer can use the isEmpty method to see if the stack is empty. This approach is
Fourth Edition Dale
Important Notes
The file includes the complete test bank, organized chapter by chapter.
A sample of selected pages has been provided for preview.
All available appendices and Excel files (if included in the original resources) are
provided.
Quizzes, Midterm and final exams are included (if available in the original resources).
We continuously update our files to ensure you receive the latest and most accurate
editions.
New editions are added regularly – stay connected for updates!
⚠️Note on Answer Keys: If the answer key is not included within the chapter
questions, you will find the complete answers and solutions at the end of each
chapter.
✅ Why Buy From Us?
📚 Complete & organized chapter-by-chapter – no missing content, no guessing.
⚡ Instant digital delivery – get your file the moment you pay, no waiting.
📅 Always up to date – we track new editions so you always get the latest version.
💬 Friendly support – real humans ready to help, anytime you need us.
🔒 Safe & secure – thousands of satisfied students trust us every semester.
🛡️Our Guarantees
💰 Money-Back Guarantee: Not satisfied? We offer a full refund – no questions asked.
🔄 Wrong File? No Problem: Contact us and we will replace it immediately with the
correct version, free of charge.
⏰ 24/7 Support: We are always here – reach out anytime and expect a fast response.
,Object-Oriented Data Structures using Java, 4th Edition
Selected Answers to Chapter 1 Exercises
Dale/Joyce/Weems
February, 2016
This file contains answers to exercises from the end of Chapter 1 of the 4th Edition of Object Oriented Data
Structures using Java. This file is intended for use only by instructors who have adopted the textbook.
Please do not post these answers on the internet. All instructors should be aware that it is possible that these
answers will be made public through carelessness or mischievous intent.
Note that we include answers for most, but not all of the exercises. We do not include answers if the
question is just a matter of opinion or of personal experience. In such cases we simply state that “answers
will vary”. Sometimes an exercise is really a “drill” rather than a question, so we don’t answer it. We do
not provide answers for major coding projects, although we may provide guidelines. Sometimes we do not
provide answers for medium sized coding projects, although we hope to provide all of these eventually
(check back later; or even better, send us your suggested solution and we will include it and give you credit
if it is appropriate). Finally, in cases where the answer to a question is found easily in the body of the text
we sometimes indicate the page number where the answer can be found, rather than repeating the
information here. The intent of such questions is for the students to describe the information in their own
words.
Chapter One – Getting Organized
Many of the questions in this chapter’s exercises are “thought questions.” The answers given here are
typical or suggested responses, but they are not the only possible answers.
Section 1 – Classes, Objects, and Applications
1. Many of the winners’ contributions dealt with programming, starting with Perlis in 1966, Dijkstra in
1972, and Knuth in 1974. But the list goes on. The winners whose work dealt primarily with object-
orientation are Wirth in 1984, Ole-Johan Dahl and Kristen Nygaard in 2001 and Kay in 2003.
2. See http://www.omg.org/gettingstarted/what_is_uml.htm#12DiagramTypes.
3. A class defines a structure or template for an object or a set of objects. An object is an instance of a
class. An example is a blueprint of a building and the building itself. Another example, from the text, of
a Java class/object is the Date class and the myDate, yourDate, ourDate objects.
4. See pages 5 and 6.
5. According to the program, the number of days between 1/1/1900 and 1/1/2000 is 36524.
Clearly there are 24 leap years.
According to the program, the number of days between 1/1/2000 and 1/1/2100 is 36525.
So that represents 25 leap years.
The difference is because 1900, being divisible by 100 is not a leap year, whereas 2000, even though it
is divisible by 100, is still a leap year because it is divisible by 400.
6. a. Answers will vary.
b. Answers will vary.
c. The number of days between11/21/1783 and 7/20/1969 is 67811
9. There are many possible “correct” answers for each part of this question. The intent was not for the
student to create code, but rather just identify a good set of variables and methods. Here are sample
,Chapter 1 / Getting Organized Page 2
answers for parts a and b:
a. Time Counter
instance variables: protected int totalMinutes;
protected int counter;
methods: public void addTime(int minutes, int seconds);
public void addTime(int minutes);
public int getTotalTime();
public int getAvgTime();
b. Basketball Statistics
instance variables: protected int score;
protected int fieldGoalsAttempted;
protected int fieldGoalsMade;
protected int freeThrowsAttempted;
protected int freeThrowsMade;
methods: public void fieldGoalMissed();
public void freeThrowMissed();
public void fieldGoalMade(int value); // value indicates 2 or 3 point shot
public void freeThrowMade();
public int getScore();
public float fieldGoalPercentage();
public float freeThrowPercentage();
Section 2 – Organizing Classes
14. See pages 12 – 16.
15. a. AbstractList
b. 3
c. 31
d. 16
e. AbstractCollection
16.
a. Legal - getDay is a public method that returns an int
b. Legal- getYear is a public method that returns an int
c. Illegal - increment is not defined for Date objects
d. Legal - increment is defined for IncDate objects
e. Legal - object variables can be assigned to objects of the same class
f. Legal - subclasses are assignment compatible with the superclasses above them in the class
hierarchy
g. Illegal - superclasses are not assignment compatible with the subclasses below them in the class
hierarchy
19. See pages19 – 21.
20. a. 15 plus 2 in support.cards
b. 5
c. i. java.io, java.util, ch05.collections, support
ii. It uses the wild card character to import all needed classes from the first three packages but it
explicitly imports the FamousPerson class from the support package
d. i. It depends on the compiler whether a syntax error is generated but in any case other classes will not
,Chapter 1 / Getting Organized Page 3
be able to import and use the class.
ii. Most compliers will simply compile the class although depending on settings you may receive a
warning.
iii. You get a syntax error since the compiler cannot locate the needed Date class.
21.
a. Yes
b. Labels
c. Length
d. records
e. media
Section 3 – Exceptional Situations
22. See page 27.
Section 4 – Data Structures
26. Answers will vary.
27. In order of occurrence:
alphabetized list of buttons sorted list
wall map two dimensional array
connections of trains linked list
ticket line queue
direct access to car 4 direct access to an array location
walking through train cars traversing a linked list
tray holder stack
Pez dispenser stack
candy machine button accessing an array
28. Answers will vary.
29.
a. Nodes are airports; edges connect airports that have flights available between them
b. Nodes are countries; edges connect countries that border each other
c. Nodes are research articles; directed edges connect articles to the articles that they reference
d. Nodes are actors; edges connect actors to the actors they have appeared in the same movies as them
e. Nodes are the computers; edges show a direct network link between the two computers
f. Nodes are rooms; edges are between rooms which have a connecting tunnel
g. Nodes are web pages; directed edges represent a hyperlink from the first page to the second
Section 5 – Basic Structuring Mechanisms
30. a.
address word
...
099
100 3
101 'c' | 'a' | 't' |
... …
123 10
124 20
...
str1: 135 100
,Chapter 1 / Getting Organized Page 4
136
b.
address word
...
099
100 3
101 'c' | 'a' | 't' |
... …
123 10
124 10
...
str1: 135 100
str2: 136 100
31. See pages 35-36
32. The output of the code would be
5/5/2000
5/5/2000
5/6/2000
5/6/2000
33. See page 36.
34. The output of the code would be
not equal
equal
equal
35. A program that meets the specifications is
//----------------------------------------------------------------------
// Exer35.java by Dale/Joyce/Weems Chapter 1
//
// Solves Chapter 1, Exercise 35
//----------------------------------------------------------------------
public class Exer35
{
public static void main(String[] args)
{
int[] squares = new int[10];
for (int i = 0; i < 10; i++)
squares[i] = i * i;
for (int i = 0; i < 10; i++)
,Chapter 1 / Getting Organized Page 5
System.out.println(squares[i]);
}
}
36. A program that meets the specifications is
//----------------------------------------------------------------------
// Exer36.java by Dale/Joyce/Weems Chapter 1
//
// Solves Chapter 1, Exercise 36
//----------------------------------------------------------------------
public class Exer36
{
public static void main(String[] args)
{
Date[] dates = new Date[10];
int month, day, year;
for (int i = 0; i < 10; i++)
dates[i] = new Date(12, i+1, 2005);
for (int i = 0; i < 10; i++)
System.out.println(dates[i]);
}
}
This solution assumes that the Date class is “visible” to the Exer36 application.
Section 7 – Comparing Algorithms: Big-O Analysis
39. Best Case: all answers are 1 – just need to be very lucky
Worst Case:
Sequential Binary
a. 10 10 4
b. 1,000 1,000 10
c. 1,000,000 1,000,000 20
d. 1,000,000,000 1,000,000,00030
40. Answers can vary. The important thing is that the student's answer is clear, and consistent.
41. The answer to the last part of the questions is:
a. approximately 1.37
b. approximately 8.87
c. 4
d. approximately 5.5
42.
a. O(N2)
b. O(N2)
c. O(N5)
d. O(N2)
e. O(N4)
f. O(N2)
,Chapter 1 / Getting Organized Page 6
43.
a. O(N)
b. O(N2)
c. O(log2N)
d. O(1)
e. O(N)
f. O(N)
44. The order of growth is O(N). A O(1) approach can be created based on the formula for the sum of the
integers between 1 … N being N (N + 1) / 2.
45.
a. O(1)
b. O(N)
c. O(N) ... even though on average takes N/2 steps, that is still O(N)
46. 27 15 83 12 104 28 57 30
12 15 83 27 104 28 57 30
12 15 83 27 104 28 57 30
12 15 27 83 104 28 57 30
12 15 27 28 104 83 57 30
12 15 27 28 30 83 57 104
12 15 27 28 30 57 83 104
12 15 27 28 30 57 83 104
End of Selected Answers to Chapter 1 Exercises
,Object-Oriented Data Structures using Java, 4th Edition
Selected Answers to Chapter 2 Exercises
Dale/Joyce/Weems
February, 2016
This file contains answers to exercises from the end of Chapter 2 of the 4th Edition of Object Oriented Data
Structures using Java. This file is intended for use only by instructors who have adopted the textbook.
Please do not post these answers on the internet. All instructors should be aware that it is possible that these
answers will be made public through carelessness or mischievous intent.
Note that we include answers for most, but not all of the exercises. We do not include answers if the
question is just a matter of opinion or of personal experience. In such cases we simply state that “answers
will vary”. Sometimes an exercise is really a “drill” rather than a question, so we don’t answer it. We do
not provide answers for major coding projects, although we may provide guidelines. Sometimes we do not
provide answers for medium sized coding projects, although we hope to provide all of these eventually
(check back later; or even better, send us your suggested solution and we will include it and give you credit
if it is appropriate). Finally, in cases where the answer to a question is found easily in the body of the text
we sometimes indicate the page number where the answer can be found, rather than repeating the
information here. The intent of such questions is for the students to describe the information in their own
words.
Chapter Two – The Stack ADT
Section 1 – Abstraction
1. Answers will vary but might include things such as driving a car using the car’s “interface” and without
knowing anything about how the engine works.
2.
a. Application level (e.g., College of Engineering’s enrollment information for 1988)
b. Abstract level (e.g., list of student academic records)
c. Implementation level (e.g., array of objects that contain the variables studentID (an integer),
lastName (a string of characters), firstName (a string of characters), etc.)
3. The efficiency of the operations.
4. An abstract method is a method declared in a class or an interface without a method body.
5. This should cause a compile time error – the compiler should not create Java bytecode for the
SampleClass. Error messages might vary across compilers. On my system I received two error
messages, both very much to the point:
SampleClass is not abstract and does not override abstract method
sampleMethod() in SampleInterface
sampleMethod() in SampleClass cannot implement sampleMethod() in
SampleInterface; attempting to use incompatible return type
6.
a. False Interfaces are not instantiated.
b. True An interface specifies some implementation requirements for a class.
c. False Only interfaces extend interfaces.
d. True Just so it also includes all of the methods listed in the interface.
e. False It must include methods for each method listed in the interface - they can be abstract
methods however.
f. False You can only instantiate objects of a concrete class.
, Chapter 2 / The Stack ADT Page 2
7. From our point of view the precondition and the described exception are redundant. The precondition
states that the number parameter will be greater than zero. So, there is no need to check for that
condition. If we need to check for that condition then it should not be stated as a pre-condition.
8. You cannot instantiate an interface like you instantiate a class to create an object. Interfaces are
typically used to define requirements for a class. You can define a class that implements an interface
and then instantiate objects of that class.
9. These answers will be similar to the implementations of Circle and Rectangle provided in the
text, except of course they must use appropriate formulas for perimeter and area.
Section 2 – The Stack
12.
a. false
b. true
c. true
d. false
e. true
f. false
g. false
h. false – not if the stack is empty
i. true
j. true
k. false
13. The classic operation both returns and removes the top element of the stack, whereas our pop operation
only removes the top element. Its return type is void.
14 a. 7 5 1
b. 2 1 3 4
c. 1 1 1 1
15.
a. Imagine placing the places the friend visited, in sequential order, onto a stack and then repeatedly
visit the place at the top of the stack, and pop it, essentially retracing their steps in reverse order
until
you find the umbrella.
b. As each higher and higher bid is made place it on a stack. Retraction of the highest bid amounts to
popping the bid off the stack.
Section 3 – Collection Elements
16. See pages 81-84.
17. The code is very straightforward.
Section 4 – Formal Specification
18. a. The stack will act as a LIFO structure.
b. A stack class will provide the operations push, pop, top, isEmpty, and isFull with the
signatures provided in the interface and functionality as described in the comments.
c. A stack object will throw exceptions if pop or top are invoked on an empty stack or if push is
invoked on a full stack.
19. An application programmer can use the isEmpty method to see if the stack is empty. This approach is
