Introduction C CC. Advanced C

Transcription

1 Introduction C C CC Advanced C i

2 ii Advanced C

3 C CIntroduction CC C CC Advanced C Peter D. Hipson A Division of Prentice Hall Computer Publishing 201 W. 103rd St., Indianapolis, Indiana USA iii

4 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 International Standard Book Number: Library of Congress Catalog Card Number: 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 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

5 Introduction C C CC Publisher Richard K. Swadley Production Analyst Mary Beth Wakefield Acquisitions Manager Jordan Gold Book Design Michele Laseau Managing Editor Neweleen A. Trebnik Cover Art Tim Amrhein Acquisitions Editor Production Editor Technical Reviewer Editorial Assistants Formatter Production Director Production Manager Stacy Hiquet Mary Corder Timothy C. Moore Rosemarie Graham Lori Kelley Pat Whitmer Jeff Valler Corinne Walls Graphic Images Specialist Production Index Dennis Sheehan Katy Bodenmiller Christine Cook Lisa Daugherty Denny Hager Carla Hall-Batton John Kane Roger Morgan Juli Pavey Angela Pozdol Linda Quigley Michele Self Susan Shepard Greg Simsic Alyssa Yesh Hilary Adams Imprint Manager Matthew Morrill Proofreading/Indexing Coordinator Joelynn Gifford v

6 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, 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

7 Introduction C C CC Overview Introduction...xxiii Part I Honing Your C Skills 1 1 The C Philosophy Data Types, Constants, Variables, and Arrays Pointers and Indirection Special Pointers and Their Usage Decimal, Binary, Hex, and Octal Separate Compilation and Linking Part II Managing Data in C C Structures Dynamic Memory Allocation Disk Files and Other I/O Data Management: Sorts, Lists, and Indexes Part III Working with Others C and Other Langauages C and Databases All About Header Files vii

8 Advanced C Part IV Documenting the Differences ANSI C s Library Functions Preprocessor Directives Debugging and Efficiency Part V Appendixes 677 A The ASCII Character Set B Compiler Variations C Introduction to C D Function/Header File Cross Reference Index viii

9 Introduction C C CC Contents Introduction...xxiii Part I: Honing Your C Skills The C Philosophy... 3 A Brief History of C and the Standard...3 A Programming Style...11 Memory Models...17 Summary Data Types, Constants, Variables, and Arrays 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

10 Advanced C 3 Pointers and Indirection 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 Special Pointers and Their Use Command Line Arguments...99 Function Pointers Menus and Pointers State Machines Summary Decimal, Binary, Hex, and Octal Decimal Binary Hex Octal Looking at a File Bit Operators Bit Fields Summary Separate Compilation and Linking Compiling and Linking Multiple Source Files Compiling Multifile Programs Linking Multifile Programs Using #include External Variables Using an Object Library Manager Using MAKE Files Summary x

11 Table Introduction of Contents Part II: Managing Data in C 189 C C CC 7 C Structures Using the struct Keyword Arrays of Structures Structures of Arrays Structures of Structures Bit Fields in Structures Using the typedef Keyword Using the offsetof() Macro Pointers to Structures Understanding unions Summary Dynamic Memory Allocation Using the malloc( ) Function Using the calloc( ) Function Using the free( ) Function Using the realloc( ) Function Allocating Arrays Global Memory versus Local Memory Summary Disk Files and Other I/O File I/O Basics Text Files and Binary Files Creating and Using Temporary Work Files Stream Files and Default File Handles The stdin File The stdout File The stderr File The stdaux File The stdprn File Low-Level I/O and File Handles Standard Low-Level File Handles Console and Port I/O Direct Port I/O xi

12 Advanced C The PC Printer Ports The PC Communications Ports Summary Data Management: Sorts, Lists, and Indexes Sorting Merging Purging Sorting, Merging, and Purging All in One Linked Lists Using Dynamic Memory Disk-Based Lists Double Linked Lists Indexing Fixed-field Disk Files B-trees Summary Part III: Working with Others C and Other Languages Other Languages Assembly FORTRAN Pascal BASIC Calling Other Languages from C Calling Assembly from C Calling FORTRAN and Pascal from C Calling C Functions from Other Languages Calling C from Assembly Calling C from FORTRAN and Pascal All the Things that Can Go Wrong Looking at Data Names and Limits Summary xii

13 Table Introduction of Contents C C CC 12 C and Databases Interfacing with dbase-compatible Programs Using dbase Files Directly Reading dbase and dbase-compatible Files Creating dbase and dbase-compatible Files Updating dbase and dbase-compatible Files Summary All About Header Files Function Prototypes The ANSI C Header Files The assert.h File (ANSI) The ctype.h File (ANSI) The errno.h File (ANSI) The float.h File (ANSI) The io.h File The limits.h File (ANSI) The locale.h File (ANSI) The malloc.h File The math.h File (ANSI) The memory.h File The search.h File The setjmp.h File (ANSI) The signal.h File (ANSI) The stdarg.h File (ANSI) The stddef.h File (ANSI) The stdio.h File (ANSI) The stdlib.h File (ANSI) String Conversion Memory Allocation Random Numbers Communications with the Operating System Search Functions Integer Math Multibyte Characters The string.h File (ANSI) The time.h File (ANSI) The varargs.h File Summary xiii

14 Advanced C Part IV: Documenting the Differences ANSI C s Library Functions Functions abort() abs() acos() asctime() asin() assert() atan() atan2() atexit() atof() atoi() atol() bsearch() calloc() ceil() clearerr() clock() cos() cosh() ctime() difftime() div() exit() exp() fabs() fclose() feof() ferror() fflush() fgetc() fgetpos() fgets() floor() xiv

15 Table Introduction of Contents C C CC fmod() fopen() fprintf() fputc() fputs() fread() free() freopen() frexp() fscanf() fseek() fsetpos() ftell() fwrite() getc() getchar() gets() gmtime() isalnum() isalpha() iscntrl() isdigit() isgraph() islower() isprint() ispunct() isspace() isupper() isxdigit() labs() ldexp() ldiv() localeconv() localtime() log() log10() longjmp() malloc() xv

16 Advanced C mblen() mbstowcs() mbtowc() memchr() memcmp() memcpy() memmove() memset() mktime() modf() offsetof() perror() pow() printf() putc() putchar() puts() qsort() raise() rand() realloc() remove() rename() rewind() scanf() setbuf() setjmp() setlocale() setvbuf() signal() sin() sinh() sprintf() sqrt() srand() sscanf() strcat() strchr() xvi

17 Table Introduction of Contents C C CC strcmp() strcoll( ) strcpy( ) strcspn( ) strerror( ) strftime( ) strlen() strncat() strncmp() strncpy() strpbrk() strrchr() strspn() strstr() strtod() strtok() strtol() strtoul() strxfrm() system() tan() tanh() time() tmpfile() tmpnam() tolower() toupper() ungetc() va_arg() va_end() va_start() vfprintf() vprintf() vsprintf() wcstombs() wctomb() printf() Format Codes c xvii

18 Advanced C e and E f g and G n o p and P s u x and X scanf() format codes c d o x i u e, f, and g n p s [...] Summary Preprocessor Directives The Macro Continuation Operator (\) The Stringize Operator (#) The Characterize Operator (#@) The Token Paste Operator (##) The Defined Identifier Operator (defined()) The #define Directive The #error Directive The #include Directive The #if Directive The #ifdef Directive The #ifndef Directive The #else Directive The #elif Directive The #endif Directive xviii

19 Table Introduction of Contents C C CC The #line Directive The #pragma Directive The message Pragma The pack Pragma The #undef Directive Predefined Macros The DATE Macro The TIME Macro The FILE Macro The LINE Macro The STDC Macro NULL The offsetof() Macro Summary Debugging and Efficiency Debugging Common Bugs Rules for Debugging Using the assert() Macro Debug Strings and Messages Debuggers Efficiency Bit Programs Compiler Optimization Direct Video I/O Floating-Point Optimization Inline Assembly Linking for Performance Pascal and cdecl Calling Conventions Precompiled Headers Using 80286/80386/80486 Instruction Sets Using a Source Profiler Using Intrinsic Functions Using Memory Models Summary xix

20 Advanced C Part V: Appendixes 677 A The ASCII Character Set B Compiler Variations Borland s C Microsoft C/C QuickC for Windows Watcom C/ C Introduction to C Object-Oriented Programming (OOP) Abstraction Encapsulation Hierarchies Learning C Overloading Functions Declaring Variables When Needed Default Function Argument Values References References as Return Values Classes D Function /Header File Cross Reference Index xx