DDAAYY 21 Teach Yourself Advanced C in 21 Days iv Teach Yourself Advanced C in 21 Days iii DDAAYY 21 Teach Yourself Advanced C in 21 Days viii Teach Yourself Advanced C in 21 Days Bradley L. Jones Gregory L. Gunt le A Division of Prentice Hall Computer Publishing 201 West 103rd Street, Indianapolis, Indiana 46290 v DDAAYY 21 Teach Yourself Advanced C in 21 Days This book is dedicated to all the people who have counted the stars at Beaubien, walked in the snows of Mt. Baldy in July, or gazed at the eagles hovering over Ponil. Like learning a programming language, going to such places takes hard work and dedication. But once they are reached, the value of the hard work is realized. To these people, this book is dedicated. Copyright © 1994 by Sams Publishing FIRST EDITION SECOND PRINTING—1994 All rights reserved. No part of this book shall be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without written permission from the publisher. No patent liability is assumed with respect to the use of the information contained herein. Although every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contained herein. For information, address Sams Publishing, 201 W. 103rd Street, Indianapolis, IN 46290. International Standard Book Number: 0-672-30471-6 Library of Congress Catalog Number: 93-87167 97 96 95 94 4 3 2 Interpretation of the printing code: the rightmost double-digit number is the year of the book’s printing; the rightmost single digit, the number of the book’s printing. For example, a printing code of 94-1 shows that the first printing of the book occurred in 1994. Composed in AGaramond and MCPdigital by Prentice Hall Computer Publishing. Printed in the United States of America Trademarks All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Sams Publishing cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or servicemark. vi Publisher Richard K. Swadley Associate Publisher Marketing Manager Production Jordan Gold Gregg Bushyeager Nick Anderson Angela D. Bannan Acquisitions Cover Designer Katy Bodenmiller Manager Dan Armstrong Ayrika Bryant Stacy Hiquet Lisa Daugherty Book Designer Stephanie Davis Kimberly K. Hannel Acquisitions Editor Michele Laseau Angela P. Judy Gregory Croy Greg Kemp Director of Stephanie McComb Development Editor Production and Jamie Milazzo Dean Miller Manufacturing Wendy Ott Jeff Valler Rochelle Palma Production Editor Nancy Sears Perry Fran Hatton Imprint Manager Casey Price Juli Cook Ryan Rader Copy Editor Kim Scott Mitzi Foster Gianakos Production Analyst Susan Shepard Tonya R. Simpson Mary Beth Wakefield Ann Sippel Editorial SA Springer Coordinator Proofreading Rebecca Tapley Bill Whitmer Coordinator Elaine Webb Joelynn Gifford Alyssa Yesh Editorial Assistants Carol Ackerman Indexing Indexer Sharon Cox Coordinator Jeanne Clark Lynette Quinn Johnna VanHoose Technical Editor Graphics Image Robert Zigon Specialists Tim Montgomery Dennis Sheehan Sue VandeWalle vii About the Authors Bradley Jones Bradley Jones is a professional programmer specializing in C development. He has helped in the development of systems for several national and international corpora- tions. As an active member of the Indianapolis Computer Society, he heads the teaching of C and C++ as a leader of the C/C++ SIG. Bradley’s other writings include co-authoring the bestseller, Teach Yourself C in 21 Days and Even You Can Soup Up and Fix PCs. He is the Chairman of the INDY PC News magazine, and is also a regular writer on topics ranging from C programming to virtual reality. Gregory Guntle Gregory Guntle has been working with microcomputers for 15 years. He has been doing technical editing for nine years. Formerly, he was manager of PC programming at RCI; he now supervises the installation and use of PCs in the company. ix DDAAYY 21 Teach Yourself Advanced C in 21 Days x Overview Introduction Week 1 at a Glance 1 Day 1 Storage Space: Working with Memory 3 2 Complex Data Types 31 3 Lists and Trees 67 4 Tapping into System Resources 103 5 Efficiency and Porting 133 6 Number Systems 169 7 Using Libraries 201 Week 2 at a Glance 227 Day 8 Tapping into System Resources via BIOS 229 9 Text Graphics (Using BIOS) 263 10 The getline() Function 295 11 Building a Routine Library 331 12 Systems Analysis and Design 353 Specification for Record of Records! Version 1.00 369 13 The User Interface: Screen Design 381 14 Enhancing the User Interface: Menuing 443 Week 3 at a Glance 479 Day 15 The User Interface: Action Bars 481 16 Help! 509 17 File Routines: The First Step 531 18 File Routines: Using Dynamic Data 587 19 Reporting 665 20 Finishing Touches: Testing, Debugging, Upgrading, and Maintaining 713 21 Where To Go from Here? 737 Appendix A Memory Models 753 B ASCII Chart 761 C C Keywords 771 D Operator Precedence 777 E ANSI Header Files 781 F Answers 785 Index 851 xi DDAAYY 21 Teach Yourself Advanced C in 21 Days xii