C C C Introduction C C C C C C C Advanced C i Advanced C ii C C C C C C Introduction C C C C C C C C C C C C C Advanced C Peter D. Hipson A Division of Prentice Hall Computer Publishing 201 W. 103rd St., Indianapolis, Indiana 46290 USA iii Advanced C © 1992 by Sams Publishing All rights reserved. Printed in the United States of America. No part of this book may be used or reproduced in any form or by any means, or stored in a database or retrieval system, without prior written permission of the publisher except in the case of brief quotations embodied in critical articles and reviews. Making copies of any part of this book for any purpose other than your own personal use is a violation of United States copyright laws. For information, address Sams Publishing, 201 W. 103rd St., Indianapolis, IN 46290 International Standard Book Number: 0-672-30168-7 Library of Congress Catalog Card Number: 92-061304 96 95 94 93 92 8 7 6 5 4 3 Interpretation of the printing code: the rightmost double-digit number is the year of the book’s printing; the rightmost single-digit number, the number of the book’s printing. For example, a printing code of 92-1 shows that the first printing of the book occurred in 1992. Composed in AGaramond and MCPdigital by Prentice Hall Computer Publishing. Screen reproductions in this book were created by means of the program Collage Plus, from Inner Media, Inc., Hollis, NH. 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 service mark. iv C C C Introduction C C C C C C C Publisher Production Analyst Richard K. Swadley Mary Beth Wakefield Acquisitions Manager Book Design Jordan Gold Michele Laseau Managing Editor Cover Art Neweleen A. Trebnik Tim Amrhein Acquisitions Editor Graphic Images Specialist Stacy Hiquet Dennis Sheehan Production Editor Production Mary Corder Katy Bodenmiller Christine Cook Technical Reviewer Lisa Daugherty Timothy C. Moore Denny Hager Carla Hall-Batton Editorial Assistants John Kane Roger Morgan Rosemarie Graham Juli Pavey Lori Kelley Angela Pozdol Linda Quigley Formatter Michele Self Pat Whitmer Susan Shepard Greg Simsic Production Director Alyssa Yesh Jeff Valler Index Production Manager Hilary Adams Corinne Walls Imprint Manager Matthew Morrill Proofreading/Indexing Coordinator Joelynn Gifford v Advanced C About the Author Peter Hipson and his wife live and work in New Hampshire. He has worked with computers since 1972, in hardware design and software development. He has developed numerous software programs for both PCs and larger systems. He holds patents in the field of CPU design and has been involved with microcomputers since their inception. Peter is the developer of the Windows applications STARmanager and STARmanager A/E. You can contact Peter Hipson at P.O. Box 88, West Peterborough, NH, 03468. Enclosing an SASE greatly enhances the likelihood of a reply. To Bianca, who has shown me what great fun it is having a granddaughter. vi C C C Introduction C C C C C C C Overview Introduction ..........................................................................xxiii Part I Honing Your C Skills 1 1 The C Philosophy...................................................................... 3 2 Data Types, Constants, Variables, and Arrays ......................... 19 3 Pointers and Indirection.......................................................... 65 4 Special Pointers and Their Usage ............................................ 99 5 Decimal, Binary, Hex, and Octal........................................... 139 6 Separate Compilation and Linking........................................ 161 Part II Managing Data in C 189 7 C Structures........................................................................... 191 8 Dynamic Memory Allocation................................................. 227 9 Disk Files and Other I/O....................................................... 249 10 Data Management: Sorts, Lists, and Indexes ......................... 321 Part III Working with Others 433 11 C and Other Langauages........................................................ 435 12 C and Databases .................................................................... 467 13 All About Header Files........................................................... 497 vii Advanced C Part IV Documenting the Differences 519 14 ANSI C’s Library Functions................................................... 521 15 Preprocessor Directives.......................................................... 621 16 Debugging and Efficiency...................................................... 641 Part V Appendixes 677 A The ASCII Character Set ....................................................... 679 B Compiler Variations .............................................................. 681 C Introduction to C++ .............................................................. 695 D Function/Header File Cross Reference .................................. 723 Index...................................................................................... 741 viii C C C Introduction C C C C C C C Contents Introduction ..........................................................................xxiii Part I: Honing Your C Skills................................................................................... 1 1 The C Philosophy...................................................................... 3 A Brief History of C and the Standard ............................................3 A Programming Style....................................................................11 Memory Models............................................................................17 Summary.......................................................................................18 2 Data Types, Constants, Variables, and Arrays ......................... 19 Data Types....................................................................................19 Constants......................................................................................25 Definitions versus Declarations .....................................................29 Declarations..............................................................................30 Definitions................................................................................33 Variables .......................................................................................35 Variable Types and Initializing Variables ..................................35 Scope (Or I Can See You).........................................................37 Life Span (Or How Long Is It Going To Be Here?)..................39 Type Casting ............................................................................41 Arrays............................................................................................46 Declaration of Arrays................................................................46 Definition of an Array...............................................................47 Array Indexing..........................................................................48 Using Array Names as Pointers.................................................55 Strings: Character Arrays...........................................................56 Using Arrays of Pointers ...........................................................58 Summary.......................................................................................62 ix Advanced C 3 Pointers and Indirection.......................................................... 65 Pointers, Indirection, and Arrays...................................................65 Pointers.........................................................................................66 Indirection ....................................................................................69 An Example of Pointers, Indirection, and Arrays...................................................................................69 Character Arrays and Strings.........................................................74 Indirection to Access Character Strings .........................................79 Protecting Strings in Memory .......................................................90 Ragged-Right String Arrays...........................................................92 Summary.......................................................................................98 4 Special Pointers and Their Use................................................ 99 Command Line Arguments...........................................................99 Function Pointers........................................................................114 Menus and Pointers.....................................................................120 State Machines............................................................................135 Summary.....................................................................................137 5 Decimal, Binary, Hex, and Octal........................................... 139 Decimal.......................................................................................139 Binary .........................................................................................141 Hex.............................................................................................142 Octal...........................................................................................144 Looking at a File .........................................................................146 Bit Operators ..............................................................................154 Bit Fields.....................................................................................155 Summary.....................................................................................158 6 Separate Compilation and Linking........................................ 161 Compiling and Linking Multiple Source Files.............................162 Compiling Multifile Programs ....................................................164 Linking Multifile Programs.........................................................164 Using #include............................................................................166 External Variables........................................................................171 Using an Object Library Manager...............................................181 Using MAKE Files......................................................................182 Summary.....................................................................................186 x