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The Student Resource Disk for Java
• Borland®JBuilder™7 Personal
• Sun Java™2 SDK Standard Edition
• Sun Java™2 SDK Standard Edition Documentation
• Program Files
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Library of Congress Cataloging-in-Publication Data
Dale,Nell B.
Programming and problem solving with Java / Nell Dale,Chip Weems,Mark Headington.
p.cm.
Includes index.
ISBN 0-7637-0490-3
1.Java (Computer program language) I.Weems,Chip. II. Headington,Mark R. III.
Title.
QA76.73.J38D346 2003
005.13’3--dc21
2002043476
All rights reserved. No part of the material protected by this copyright notice may be repro-
duced or utilized in any form,electronic or mechanical,including photocopying,recording,or
any information storage or retrieval system,without written permission from the copyright
owner.
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This book is dedicated to you,and to all of our other students for
whom it was begun and without whom it would never have
been completed.
To quote Mephistopheles,one of the chief devils,and tempter of
Faust,
…My friend,I shall be pedagogic,
And say you ought to start with Logic…
…Days will be spent to let you know
That what you once did at one blow,
Like eating and drinking so easy and free,
Can only be done with One,Two,Three.
Yet the web of thought has no such creases
And is more like a weaver’s masterpieces;
One step,a thousand threads arise,
Hither and thither shoots each shuttle,
The threads flow on,unseen and subtle,
Each blow effects a thousand ties.
The philosopher comes with analysis
And proves it had to be like this;
The first was so,the second so,
And hence the third and fourth was so,
And were not the first and second here,
Then the third and fourth could never appear.
That is what all the students believe,
But they have never learned to weave.
J.W.von Goethe,Faust,Walter Kaufman trans.,New York,Anchor/Doubleday: 1963.
As you study this book,do not let the logic of algorithms
bind your imagination,but rather make it your tool for weaving
masterpieces of thought.
Contents
Preface xv
Chapter 1 Introduction to Object-Oriented Programming 2
1.1 Overview of Object-Oriented Programming 4
What Is Programming? 4
How Do We Write a Program? 5
1.2 How Is Java Code Converted into a Form That a
Computer Can Use? 10
1.3 How Does Interpreting Code Differ from Executing It? 14
1.4 How Is Compilation Related to Interpretation and
Execution? 14
1.5 What Kinds of Instructions Can Be Written in a
Programming Language? 15
Object-Oriented Programming Languages 18
1.6 What’s Inside the Computer? 20
1.7 Problem-Solving Techniques 22
Ask Questions 23
Look for Things That Are Familiar 24
Solve by Analogy 25
Means-Ends Analysis 25
Divide and Conquer 26
The Building-Block Approach 27
Merging Solutions 27
Mental Blocks: The Fear of Starting 28
Object-Oriented Problem Solving 29
Case Study: Party Planning 30
Summary 33
Quick Check 34
Exam Preparation Exercises 36
Programming Warm-Up Exercises 37
Programming Problems 38
Case Study Follow-Up 38
Chapter 2 Java Syntax and Semantics,Classes,and Objects 40
2.1 The Elements of Java Programs 42
Syntax and Semantics 42
Syntax Templates 42
Naming Program Elements: Identifiers 46
Built-in Types in Java 47
Classes and Objects 50
Defining Terms: Declarations 54
v
vi | Contents
Field Declarations 54
Assignment and Expressions 59
Beyond Minimalism: Adding Comments to Code 64
Output 64
Input 67
Interactive Input and Output 70
2.2 Application Construction 70
Blocks 73
2.3 Application Entry,Correction,and Execution 75
Entering Application Code 75
Compiling and Running an Application 77
Finishing Up 77
2.4 Classes and Methods 78
User Classes 78
Methods 79
Case Study: Display a Name in Multiple Formats 83
2.5 Testing and Debugging 86
Summary 87
Quick Check 88
Exam Preparation Exercises 90
Programming Warm-Up Exercises 94
Programming Problems 95
Case Study Follow-Up 97
Chapter 3 Arithmetic Expressions 98
3.1 Overview of Java Data Types 100
3.2 Numeric Data Types 103
Integral Types 103
Floating-Point Types 105
3.3 Declarations for Numeric Types 106
Named Constant Declarations 106
Variable Declarations 107
3.4 Simple Arithmetic Expressions 108
Arithmetic Operators 108
Increment and Decrement Operators 112
3.5 Compound Arithmetic Expressions 114
Precedence Rules 114
Type Conversion and Type Casting 115
3.6 Additional Mathematical Methods 120
3.7 Value-Returning Class Methods 122
3.8 Additional String Operations 126
Contents | vii
The length Method 126
The indexOf Method 126
The substring Method 128
Converting Strings to Numeric Values 130
Noninteractive Input/Output 131
3.9 Applications with Multiple Class Files 131
Case Study: Small Company Payroll 135
3.10 Testing and Debugging 140
Summary 141
Quick Check 141
Exam Preparation Exercises 143
Programming Warm-Up Exercises 146
Programming Problems 150
Case Study Follow-Up 151
Chapter 4 Selection and Encapsulation 152
4.1 Flow of Control 154
Selection 154
4.2 Conditions and Logical Expressions 154
The boolean Data Type 155
Logical Expressions 155
Precedence of Operators 165
Relational Operators with Floating-Point Types 167
4.3 The if Statement 167
The if-else Form 168
Blocks (Compound Statements) 169
The if Form 170
4.4 Nested if Statements 173
The Dangling else 176
4.5 Encapsulation 177
4.6 Abstraction 179
Data and Control Abstraction 179
Case Study: Warning Notices 184
4.7 Testing and Debugging 190
Testing Strategies 190
The Test Plan 193
Tests Performed Automatically During Compilation and
Execution 194
Summary 197
Quick Check 197
Exam Preparation Exercises 199
Programming Warm-Up Exercises 204
viii | Contents
Programming Problems 206
Case Study Follow-Up 209
Chapter 5 File Objects and Looping Statements 210
5.1 File Input and Output 212
Files 212
Using Files 213
An Example Application Using Files 219
5.2 Looping 220
The while Statement 221
Phases of Loop Execution 223
Loops Using the while Statement 223
Count-Controlled Loops 223
Event-Controlled Loops 225
Looping Subtasks 229
How to Design Loops 233
Designing the Flow of Control 233
Designing the Process Within the Loop 235
The Loop Exit 236
Nested Loops 236
General Pattern 237
Designing Nested Loops 240
5.3 Mutable and Immutable Objects 242
A Parameter-Passing Analogy 244
Case Study: Average Income By Gender 246
5.4 Testing and Debugging 252
Loop-Testing Strategy 252
Test Plans Involving Loops 252
Summary 255
Quick Check 257
Exam Preparation Exercises 258
Programming Warm-Up Exercises 262
Programming Problems 264
Case Study Follow-Up 266
Chapter 6 Object-Oriented Software Design and Implementation 268
6.1 Software Design Strategies 270
6.2 Objects and Classes Revisited 271
6.3 Object-Oriented Design 274
Object-Oriented Problem Solving 275
Software Engineering 276
6.4 The CRC Card Design Process 277
Identifying the Initial Classes Through Brainstorming 277
Contents | ix
Filtering 278
Determining Responsibilities 280
Inheritance 285
6.5 Functional Decomposition 285
Writing Modules 287
6.6 Object-Oriented Implementation 289
Class Interface Design 289
Internal Data Representation 291
Responsibilities as Methods 292
6.7 Packages 294
Package Syntax 294
Packages with Multiple Compilation Units 296
Package Example 297
6.8 Ethics and Responsibilities in the
Computing Profession 301
Software Piracy 301
Privacy of Data 302
Use of Computer Resources 302
Case Study: Address Book 304
6.9 Testing and Debugging 314
Summary 315
Quick Check 316
Exam Preparation Exercises 317
Programming Warm-Up Exercises 319
Programming Problems 320
Case Study Follow-Up 323
Chapter 7 Inheritance,Polymorphism,and Scope 324
7.1 Inheritance 326
An Analogy 326
7.2 Inheritance and the Object-Oriented Design Process 328
7.3 How to Read a Class Hierarchy 333
Overriding 336
Hiding 336
Polymorphism 337
7.4 Derived Class Syntax 337
7.5 Scope of Access 339
Internal Scope 340
External Scope 342
7.6 Implementing a Derived Class 346
Constructors in Derived Classes 347
