Table Of ContentRICHARD JOHNSONBAUGH
MARTIN KALIN
Object-OnammiPnrgo gir riented
C++
Object-Oriented
Programming in C + +
Richard Johnsonbaugh
Martin Kalin
DEPAUL UNIVERSITY
PRENTICE HALL, Englewood Cliffs, New Jersey 07632
Cover photograph: Autograph score of Schubert’s Great C major Symphony,
Gesellschaft der Musikfreunde.
Used by permission
Copyright © 1995 by Prentice-Hall, Inc.
A Paramount Communications Company
Englewood Cliffs, New Jersey 07632
All rights reserved. No part of this book may be
reproduced in any form or by any means,
without permission in writing from the publisher.
Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
ISBN 0-05-3bDbfl2-7
Prentice-Hall International (UK) Limited, London
Prentice-Hall of Australia Pty. Limited, Sydney
Prentice-Hall Canada Inc., Toronto
Prentice-Hall Hispanoamericana, S.A., Mexico
Prentice-Hall of India Private Limited, New Delhi
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Simon & Schuster Asia Pte. Ltd., Singapore
Editora Prentice-Hall do brasil, Ltda., Rio de Janiero
Trademark Notices
IBM is a registered trademark of International Business Machines Corpora
tion.
UNIX is a registered trademark of AT&T Bell Laboratories.
Borland C++, Turbo C, and Turbo C++ are registered trademarks of Bor
land International, Inc.
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Preface
This book is based on C++ courses given by the authors at DePaul Univer
sity for the last several years. The book can be used for self-study or a course
on object-oriented programming in C++. We assume no prior knowledge of
C++, but we do assume knowledge of C. This book is truly about C++, and
not simply about the C subset of C++. Coverage of C at the level provided
in R. Johnsonbaugh and M. Kalin, Applications Programming in ANSI C,
3rd ed. (New York: Macmillan, 1995) provides sufficient background for this
book. In this book, as in our C books, we make extensive use of examples,
figures, self-study exercises, sample applications, lists of common program
ming errors, and programming exercises. We strive for clarity throughout
the book and also illustrate a variety of good programming style possible in
C++. Our aim is to make C++ the language of choice for those who need
the power of object-oriented programming.
This is the first introductory book on C++ that treats object-oriented
design, emphasizes sound programming practices (see, e.g., Assertions and
Program Correctness, Section 3.8), presents the C++ input/output class
hierarchy (Chapter 7) in sufficient detail so that it can be used, and features
major, useful examples (e.g., Measuring Computer Performance, Section 5.3,
and A Random Access File Class, Section 7.6).
C++ is an evolving language; hence, no final standard has yet been es
tablished. The C++ presented in this book is based on the latest Working
Paper for Draft Proposed International Standard for Information Systems—
Programming Language C++ developed by the X3J16 standards committee
of The American National Standards Institute (ANSI). The X3J16 commit
tee is developing a definition of C++, which eventually will evolve into a
proposed standard. The Working Paper is available from
Standards Secretariat CBEMA
1250 Eye Street, NW
Suite 200
Washington, DC 20005
viii PREFACE
Overview
During the 1980s and 1990s, C became the language of choice for many
applications and systems programmers. Most major software available for
personal computers is written in C: spreadsheets, word processors, databases,
communications packages, statistical software, graphics packages, and so on.
Virtually all software written for the UNIX environment is likewise written
in C, and many mainframe systems meant to be ported from one platform
to another are also coded in C. In the early 1980s, Bjarne Stroustrup of
AT&T Bell Labs developed C++ as an extension of C that supports object-
oriented programming, a type of programming that is well suited to the large,
complex software systems now written for all platforms, from the cheapest
personal computers to the most expensive mainframes. C++ also corrects
some shortcomings in C, which C++ includes as a subset, and it supports
abstract data types. C++’s popularity has grown in tandem with that of
object-oriented design in software. Accordingly, we cover object-oriented
design and C++ programming.
C++ is a complex language. Fortunately, most C++ programmers can
benefit from its power without mastering each and every one of its features.
Because ours is an introductory book, we focus on the most useful aspects
of the language; but we also cover all of the language’s constructs. We
emphasize using C++ to write practical applications based on sound object-
oriented design.
The book includes the following features:
• Examples and exercises that cover a wide range of applications.
• Sample applications.
• A broad variety of programming exercises. The book contains 59 pro
gramming exercises.
• End-of-chapter lists of common programming errors.
• Discussion of the standard C++ input/output class library (Chapter
7).
• Self-study exercises to enable readers to check their mastery of a section.
The book contains nearly 500 such exercises. Answers to the odd-
numbered exercises are in the back of the book.
• Figures to facilitate the learning process.
• Major data structures, including stacks (Section 3.2), strings (Section
4.1), binary search trees (Section 4.4), and files (Section 7.6), imple
mented in C++.
• A number of appendixes.
• Understandable code. We opt for clarity over subtlety throughout the
book.
PREFACE ix
• The latest C++ features including templates (Section 3.9), exception
handling (Section 8.1), run-time type identification (Section 8.2), and
namespaces (Section 8.3).
• An introduction to the object-oriented languages Smalltalk, Eiffel, and
Objective C (Section 8.4).
Organization of the Book
Chapter 1 introduces key concepts associated with object-oriented design
and programming: classes, abstract data types, objects, inheritance, encap
sulation, polymorphism, and others. The chapter contrasts object-oriented
design with top-down functional decomposition and offers examples to illus
trate the difference between the approaches.
Chapter 2 discusses some important changes from C to C++. It also
introduces C++ input/output so that the reader can begin using this class
library right away. Chapter 7 goes into the details of C++ input/output.
Chapters 3 and 4 are devoted to classes. Chapter 3 covers the basics so
that the reader can begin using classes at once. The chapter explains how to
declare classes; how to write constructors, destructors, and other methods;
how to overload operators; and how to write friend functions. Chapter
3 introduces assertions as a tool to promote correctness in object-oriented
programs. Chapter 3 also introduces templates and encourages their use for
constructing generic classes. We believe that assertions and templates have
not received adequate coverage in other C++ books, particularly given their
power to promote the goals of object-oriented design. Chapter 4 expands
on Chapter 3 and introduces new material as well. Constructors are studied
closely, friend classes are presented, and static data members and meth
ods are introduced. Chapters 3 and 4 rely heavily on examples to explain
how classes may be used to implement abstract data types and to meet the
object-oriented goal of encapsulation.
Chapter 5 explains inheritance (including multiple inheritance) and poly
morphism in depth. Through examples and sample applications (e.g., mea
suring computer performance, polymorphic tree traversal), the chapter il
lustrates basic programming techniques and also illustrates different styles
of C++ programming. The chapter carefully explains the distinction be
tween run-time and compile-time binding so that the reader is clear about
the limits of polymorphism in C++.
Chapter 6 is devoted to operator overloading. The chapter first reviews
earlier treatments of the topic and then offers many examples and several
sample applications to highlight the power of operator overloading. The
chapter shows how to overload the subscript, function, memory management,
preincrement, and postincrement operators among others.
Chapter 7 serves two purposes. First, the chapter examines in detail
the C++ input/output library so that the interested reader can exploit the
powerful classes contained therein. This treatment culminates in a sample
X PREFACE
application that builds a random access file class through inheritance from
a library file class. Second, the chapter uses the input/output library as
a major, sophisticated example of object-oriented design realized in C++.
Chapter 7 pays close attention to manipulators, which are powerful ways
to do sophisticated input/output in C++. We believe Chapter 7 offers an
unrivaled examination of C++’s input/output.
Chapter 8 covers advanced topics such as exception handling, run-time
type identification, and namespaces. These topics are recent additions to
C++. The chapter also contrasts C++ with other object-oriented languages
such as Eiffel, Objective C, and Smalltalk. The chapter concludes with a
discussion of the future of object-oriented design and programming.
This book is devoted to C++ independent of any particular operating
system. However, the basic commands needed to run C++ programs are
given in Appendixes C and D for the UNIX g++ and Borland C++ compilers.
In addition, Appendix C contains an extended discussion of UNIX.
We rely heavily on short examples, pictures, tables, and other figures to
illustrate specific points about the syntax and semantics of C++. From our
experience in teaching C++ and other languages, we are convinced that no
single method is appropriate for clarifying every aspect about a language.
Most of our students agree with us that learning and using C++ is fun.
We have tried to incorporate this view by using interesting examples, sample
problems, programming exercises, and short slices of code.
Chapter Structure
The chapters are organized as follows:
Contents
Overview
Section
Section Exercises
Section
Section Exercises
Common Programming Errors
Programming Exercises
In Chapters 3 through 7, several sections are devoted to sample applica
tions. Each of these sections contains a statement of a problem, a solution to
the problem, and an implementation of a solution to the problem in C++.
Many of these sections conclude with an extended discussion.
The sample applications include the following:
• A stack class (Section 3.2)
• A zip code class (Section 3.4)
• A complex number class (Section 3.6)
PREFACE xi
• A string class (Section 4.1)
• A binary search tree class (Section 4.4)
• Iterators (Section 4.5)
• Measuring computer performance (Section 5.3)
• An associative array (Section 6.4)
• Random access files (Section 7.6)
The Common Programming Errors sections highlight those aspects of the
language that are easily misunderstood. The book contains 59 programming
exercises drawn from a wide variety of applications.
Exercises
The book contains nearly 600 section review exercises, the answers to which
are short answers, code fragments, and, in a few cases, entire programs.
These exercises are suitable as homework problems or as self-tests. The
answers to the odd-numbered exercises are in the back of the book, and
the answers to the even-numbered exercises are in the Instructor’s Guide.
Our experience teaching C++ has convinced us of the importance of these
exercises.
The applications covered in the programming exercises at the ends of the
chapters include the following:
• Semaphores (Programming Exercise 3.7)
• Local area networks (Programming Exercises 4.3 and 5.2)
• Scheduling (Programming Exercise 4.7)
• Graphs (Programming Exercises 4.9 and 5.6)
• Spreadsheets (Programming Exercises 4.8 and 6.9)
• Indexed files (Programming Exercise 7.5)
Not every reader will be interested in all of these applications; however, we
think that it is important to show the variety of problems that C++ can
address.
Appendixes
Four appendixes are provided for reference. Appendix A contains the ASCII
table. Appendix B contains a list of some of the most useful C++ functions
and class methods. We describe the parameters and return values for each,
the header file to include (when specified), and what the function or method
does.
For those readers using C++ under UNIX, we have included Appendix
C. We describe the GNU C++ compiler command g++ in some detail. In ad
dition to the g++ command, we also discuss the make utility, the file system,
commands for handling files (e.g., Is, cp), directories and several commands
