Programming and Problem Solving with Ada 95, Second Edition Nell Dale Chip Weems John McCormick Jones and Bartlett Programming and Problem Solving with Ada 95 Second Edition Programming and Problem Solving with Ada 95 Second Edition Nell Dale University of Texas, Austin Chip Weems University of Massachusetts, Amherst John McCormick University of Northern Iowa, Cedar Falls World Headquarters Jones and Bartlett Publishers 40 Tall Pine Drive Sudbury, MA 01776 978-443-5000
[email protected] www.jbpub.com Jones and Bartlett Publishers Canada 2406 Nikanna Road Mississauga, Ontario CANADA L5C 2WG CHIEF EXECUTIVE OFFICER: Clayton Jones CHIEF OPERATING OFFICER: Don W. Jones, Jr. V.P., SALES AND MARKETING: Tom Manning V.P., COLLEGE EDITORIAL DIRECTOR: Brian L. McKean V.P., MANAGING EDITOR: Judith H. Hauck V.P., DESIGN AND PRODUCTION: Anne Spencer NATIONAL SALES MANAGER: Paul Shepardson SENIOR MARKETING MANAGER: Jennifer M. Jacobson SENIOR ACQUISITIONS EDITOR: J. Michael Stranz PRODUCTION EDITOR: Rebecca S. Marks DIRECTOR OF MANUFACTURING AND INVENTORY CONTROL: COVER DESIGN: Stephanie Torta TEXT DESIGN: George McLean COMPOSITION: PageMasters & Company PRINTING AND BINDING: Courier Companies COVER PRINTING: Courier Companies Jones and Bartlett Publishers International Barb House, Barb Mews London W6 7PA UK Therese Bräuer Copyright 2000 by Jones and Bartlett Publishers, Inc. All rights reserved. No part of the material protected by this copyright notice may be reproduced 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. Library of Congress Cataloging-in-Publication Data Dale, Nell B. Programming and problem solving with ADA / Nell Dale, Chip Weems, John McCormick.—2nd ed. p. cm. Includes index. ISBN: 0-7637-0792-9 1. Ada (Computer program language) I. Weems, Chip II. McCormick, John (John W.) III. Title. QA76.73.A35 D36 2000 005.13'3—dc21 Printed in the United States of America 04 03 02 01 00 10 9 8 7 6 5 4 3 2 1 99-049488 This book is dedicated to you, and to all of our students, for whom it was begun and without whom it could never have been completed. N. D. C. W. J. M. To Naomi, wife and best friend. J. M. Contents P R E FA C E xxi AC K N O W LE D G M E NTS 1 O V E R V I E W O F P R O G R A M M I N G A N D P R O B LE M S O LV I N G Overview of Programming xxix 1 2 What Is Programming? What Is a Computer? Background Information: Mainframes, Micros, and Minis How Do We Write a Program? Theoretical Foundations: Data Representation What Is a Programming Language? 2 3 9 13 18 19 Problem-Solving Techniques 23 Ask Questions Look for Things That Are Familiar Solve by Analogy Means-Ends Analysis Divide and Conquer The Building-Block Approach Merging Solutions How to Start Algorithmic Problem Solving Software Engineering Programming at Many Scales 25 25 26 27 27 28 29 29 30 30 31 viii Contents The Ada Programming Language Background Information: The Origins of Ada Problem-Solving Case Study: A Company Payroll 33 35 37 Summary 42 Quick Check Answers Exam Preparation Exercises Programming Warm-up Exercises 2 A DA SYNTAX, S E M A NTI C S, A N D TH E P R O G R A M D E V E LO P M E NT P R O C E S S The Elements of Ada Programs 43 44 44 46 47 48 Syntax and Semantics Identifiers Matters of Style: Using