Data abstraction and structures using C++

688 Pages·1996·45.55 MB·English

by  Mark R. Headington

DATA ABSTRACTION AND

STRUCTURES USING C++
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DATA ABSTRACTION AND

STRUCTURES USING C++

Mark R. Headington
University of Wisconsin-La Crosse
David D. Rdey
University of Wisconsin-La Cmse
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Cover: James Crable “Enipire State Plaza, Albany, NY.” Reproduced courtesy of’J.J
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Library of Congress Catalog Number: 92 -7 5664
ISBN 0-7637-029 5-1
Printed in the United States of America
03 02 01 00 99 10 9
To Anne, Brady, and Kari, who haven’t seen much of me in the
last three years.
LM. R. H.
To my wife, Sandi, and children, Derek and Kasandra.
D. D. R.
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PREFACE

Software design has evolved dramatically in the past decade. In the 1970s,
structured programming changed the way that programmers viewed control
structures. More recently, the concepts of data abstraction and object-oriented
software development have affected the way that programmers view data
structures. Introductory computer science courses must embrace these tech-
niques if they are to provide an adequate foundation in contemporary sofixare
development.
About This Book
Data Abstraction and Stmctzwes Using C++ is designed for a second course in
computer science fundamentals, consistent with the AChI guidelines for the
CS2 course (August 1985). The book is also compatible with a Cl02 course in
ACMAEEE’s Computing Curricula 1991, covering elements from the follow-
ing knowledge units: ALl through AL4, AL6, SE1 through SES, and PL3
through PL6.
The text’s emphasis is on abstraction and its role in software development.
The first chapter reviews (and extends) the principles of control abstraction
that students learn in the first computer science course. Chapter 2 serves as a
bridge between control abstraction and data abstraction, introducing separate
compilation and the use of header files to separate specification from im-
plementation. From Chapter 3 forward, the focus is on data abstraction-
the separation of a data type’s abstract properties from the details of its
implementation,
Although this text is intended primaril?. for the second computer science
course, it also can be used in a sophomore/junior-level data structures course
(CS7) when supplemented with more advanced material on data structures.
Prerequisite Knowledge
This text assumes that the student has completed a first course in computer
science that examined the tools and techniques of structured programming in a
modern language-Pascal, iuodula-2, Ada, C, C++, or Scheme, for example.
Prior knowledge of C++is not required. Ij’e have provided three appendices
to aid in the transition from another language to C++,and it is in these appen-
dices that many readers will want to begin. Appendix A (Introductory
VI I
Comparison of Pascal and C++)is a starting point for students with no
background in C or C++. Appendix B (Introductory Comparison of C: and
C++)serves as a brief introduction to C++for those already familiar with C.
Appendix C (C++S tream I/O) coiripletes the introduction to C++and should
be read after either Appendix A or Appendix B.
The Use of C++
This book originated in response to the rapid adoption of C and C++in the
commercial arena and in academic curricula. A number of educators have
expressed concern about the use of these languages, faulting them for being
too unconstrained and for encouraging a tricky, unreadable style of program-
ming. But it is well known that one can write bad code in any language. This
text’s approach is to present the language and program examples in a very dis-
ciplined manner so that potentially confusing coding practices (such as abun-
dant use of side effects) do not obscure the primary subject: data abstraction
and data structures.
The choice of C++over C was a very clear one. C++extends the C lan-
guage to provide linguistic support for information hiding and abstract data
types as well as for object-oriented programming (OOP). Regarding the lat-
ter, we have placed the material on object-oriented design and OOP in
Chapters 10 and 11. We believe that these techniques are better appreciated,
even nahiral, after a thorough grounding in the design and implenientation of
abstract data types. However, instructors wanting an earlier introduction to
these topics will find tlexibiliq in the chapter organization.
Distinguishing Features
Separation of Data Structure Definitions from Their Implementations
Students often confuse the abstract properties of a data structure with its
implementation. hlost textbooks interweave implementation issues M ith dis-
cussion of a data structure’s characteristics and applications. A common result
is that upper-division students almost invariably associate linked lists with
dynamic data and machine-level pointers. They are surprised to learn (or
remember) that alternative data representations exist and that an arrajr of
records using subscripts as “pointers” is in fact the preferred alternative for
time-critical applications such as operating system software.
In this test, Part I (Abstraction) includes a chapter introducing well-known
data structures as abstract data types. Their characteristics and applications are
discussed without reference to possible implementations so students will be
less apt to confuse abstract properties with implementation. Part I1 (Tools for
Irnplementation) develops techniques and algorithms that culminate in alter-
native iinplernentations of the major data structures.
Software Design Features
To highlight the importance of good program design techniques, we have
sprinkled many separate Designiiig uyith Wisdom, Using the Lnngrrnge, and
Pzrrsuing Coi7-ect7iess sections throughout the text. ilidditionally, nearly ever).
chapter has a special section entitled A Studjt in Desipi, an in-depth exposition
of the development of a particular program, module, or abstract data qpe.
Development of Tools and Techniques
Every programmer needs a toolbox. This book includes numerous tools for
the developing software engineer. Ariiong these tools are modules, abstract
data types, module and class interface diagrams, assertions, recursion, table-
driven code, primitive models for data, Backus-Naur Form, performance
analysis, and many widely used data structures with associated algorithms.
Assertions
We use assertions in the form of program comments throughout the text.
Functions are documented with preconditions and postconditions to define
precisely the contract between the caller and the called routine. Loop invari-
ants document the semantics of loops. In addition, class invariants are intro-
duced as a method of defining the expected behavior of class objects.
Appendix D summarizes the assertion notation used in the book.
Problem Specification Form
We use a six-part problem specification form to emphasize the importance of
precise and complete specifications. This form consists of the title, problem
description, input specifications, output specifications, error handling, and a
sample program execution. We frequently present larger programming exam-
ples and programming project assignments in this form.
Terminology
The computer scientist needs an extensive vocabulary. To build and reinforce
this essential vocabulary, we accent important terms in boldface in the text and
list them in a Key Terms section at the end of every chapter.
Extensive Selection of Examples
Most students learn by example. The text therefore includes many care-
fully selected examples illustrating program design and C++code. Il’e have