[Ronald ^Iteock Reigafe Manual Writers CAMBRIDGE UNIVERSITY PRESS CAMBRIDGE NEW YORK PORT CHESTER MELBOURNE SYDNEY CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, Sao Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK Published in the United States of America by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambridge.org/9780521468213 © Cambridge University Press 1992 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 1992 Reprinted (with corrections and in a larger format) 1993 Reprinted 1998 Re-issued in this digitally printed version (with corrections) 2008 A catalogue record for this publication is available from the British Library ISBN 978-0-521-46821-3 paperback Acknowledgements l^y warmest thanks to the following people without whom the job of writing this book would have been lonely and terrifying: Paul Burden, for patiently steering my rambling thoughts from nonsense to sense during many telephone conversations; Mike Ingham, for the same thing, and making it worth while to continue instead of throwing it all in the bin; Paul Shearing, for his enthusiasm and indispensable help with production; Andrew, my elder son, for help with just about everything. PREFACE OTHER OPERATORS 45 ri SUMMARY 46 ^INTRODUCTION 1 PRECEDENCE & ASSOCIATIVITY 47 MIXED TYPES 48 CONCEPTION 2 PROMOTION & DEMOTION 48 REALIZATION 4 CAST 48 DISSECTION 6 PARAMETERS 48 EXERCISES 10 LITERAL CONSTANTS 48 ACTION OF OPERATORS 49 CONCEPTS 11 - L (jONTROL 51 DECISIONS 12 ^ IF - ELSE 12 TESTED LOOPS 52 LOOPS 14 COUNTED LOOP 53 CHARACTERS 15 ESCAPE 53 ARRAYS 16 AREA OF A POLYGON 54 MATRIX MULTIPLICATION 17 SELECTION STATEMENT - IF 55 HOOKE'S LAW 18 ROMAN NUMBERS 56 FUNCTIONS 20 SWITCH 58 CALL BY VALUE 21 JUMP 59 RATE OF INTEREST 22 CABLES 60 SCOPE OF VARIABLES 23 QUICKSORT 62 RECURSION 24 EXERCISES 64 EXERCISES b s—•>. ) ORGANIZATION 65 COMPONENTS 27 PROCESSING 66 NOTATION 28 PREPROCESSOR 67 CHARACTERS 29 SIMPLE MACROS 68 NAMES 30 MACROS WITH ARGUMENTS 68 SCALAR TYPES 31 NESTED MACROS 69 ON YOUR MACHINE... 32 STRING ARGUMENTS 69 CONSTANTS 33 HEADER FILES 70 LITERAL CONSTANTS 33 FUNCTION PROTOTYPES 70 STRING LITERALS 33 CONDITIONAL PREPROCESSING 71 NAMED CONSTANTS 34 SYNTAX SUMMARY 72 ENUMERATIONS 34 STORAGE CLASS 73 EXPRESSIONS 35 OUTSIDE DECLARATIONS 74 STATEMENTS AND PROGRAM 36 BLOCK DECLARATIONS 76 DECLARATIONS 37 PARAMETER DECLARATIONS 77 DECLARATION VS DEFINITION 37 NAME SPACE 78 FUNCTION DEFINITION 37 s% 38 V£ PROTOTYPES f JOINTERS, ARRAYS, STRINGS 79 OLD-STYLE C 38 HEADER FILES 38 POINTERS 80 OPERATORS 39 * OPERATOR 80 ARITHMETIC OPERATORS 39 & OPERATOR 80 LOGICAL OPERATORS 39 DECLARING POINTERS 81 BITWISE OPERATORS 40 PARAMETERS 82 ASSIGNMENT OPERATORS 42 QUICKSORT AGAIN 83 INCREMENTING OPERATORS 43 POINTER ARITHMETIC 84 SEQUENCE OPERATOR 43 PARLOUR TRICK 86 REFERENCE OPERATORS 44 POINTERS TO FUNCTIONS 88 vu COMPLEX DECLARATIONS 90 DYNAMIC STORAGE 143 STRINGS 92 STRING ARRAYS 93 MEMORY ALLOCATION 144 STRING POINTERS 93 STACKS 146 PRINTING STRINGS 94 POLISH AGAIN 148 RAGGED ARRAYS 94 SIMPLE CHAINING 149 COMMAND LINE 95 SHORTEST ROUTE 150 INTRODUCING RINGS 154 PARAMETER COUNTING 96 STRING UTILITIES 98 ROSES 156 READ FROM KEYBOARD 98 BINARY TREES 158 MONKEY PUZZLE 161 WHAT KIND OF CHARACTER? 100 EXERCISES 162 HOW LONG IS A STRING? 100 COPYING STRINGS 101 LIBRARY 163 COMPARING STRINGS 102 BACKSLANG 104 INPUT, OUTPUT, FILES 164 EXERCISES 106 LOW LEVEL I/O 164 SINGLE CHARACTER I/O 164 4JNPUT, OUTPUT 107 FILE MANAGEMENT 165 RANDOM ACCESS 166 ONE CHARACTER 108 STRING I/O 167 GET 108 FORMATS FOR I/O 168 PUT 109 TEMPORARY FILES 170 UNGET 109 BUFFERING 170 PRINT FORMAT 110 PROCESS CONTROL 171 SCAN FORMAT 112 TERMINATION 171 EASIER INPUT 114 LOCALE 173 STREAMS AND FILES 116 ERROR RECOVERY 174 OPENING 116 SIGNALS, EXCEPTIONS 175 CLOSING 117 VARIABLE ARGUMENT LIST 176 REWINDING 117 MEMORY ALLOCATION 176 REMOVING 117 STRING TO NUMBER 177 RENAMING 118 MATHEMATICS 179 ERRORS 118 ARITHMETICAL 180 CATS 119 TRIGONOMETRICAL 181 TEMPORARY FILES 120 HYPERBOLICS 182 BINARY I/O 121 RANDOM NUMBERS 182 RANDOM ACCESS 122 MODULAR DIVISION 183 DATABASE 123 LOGARITHMS, EXPONENTIALS 184 CHARACTERS 185 EXERCISES Yte STRINGS 186 STRING LENGTH 187 STRUCTURES, UNIONS 125 COPY & CONCATENATE 187 STRING COMPARISON 188 STRING SEARCH 189 INTRODUCING STRUCTURES 126 MISCELLANEOUS STRINGS 190 USAGE OF STRUCTURES 128 SORT, SEARCH 191 ACCESS OPERATORS 129 DATE AND TIME 192 STYLE OF DECLARATION 130 BOOKLIST 131 SUMMARIES 195 UNIONS 132 BIT FIELDS 133 OPERATOR SUMMARY 196 SYNTAX 134 SYNTAX SUMMARY 197 TYPE OR SHAPE 134 LIBRARY SUMMARY 204 ALIAS 134 DECLARATORS 135 TYPE-NAME 135 BIBLIOGRAPHY 209 DECLARATION 136 STACKS 138 REVERSE POLISH NOTATION 139 POLISH 141 LNDEX 210 EXERCISES 142 VIU Ijhe original C programming language was devised by Dennis Ritchie. The first book on C, by Kernighan and Ritchie, came out in 1978 and remained the most authoritative and best book on the subject until their second edition, describing ANSI standard C, appeared in 1988. In all that time, and since, the availability and use of C has increased exponentially. It is now one of the most widely used programming languages, not only for writing computer systems but also for developing applications. n are many books on C but not so many on ANSI standard C which is the version described here. ^fhis book attempts three things: • to serve as a text book for introductory courses on C aimed both at those who already know a computer language and at those entirely new to computing • to summarize and present the syntax and grammar of C by diagrams and tables, making this a useful reference book on C • to illustrate a few essential programming techniques such as symbol state tables, linked lists, binary trees, doubly linked rings, manipulation of strings, parsing of algebraic expressions. I/or a formal appreciation of Ca its p>ower, its advantages and dis- advantages *=* see the references given in the Bibliography. As an informal appreciation: all those I know who program in C find the language likeable and enjoy its power. Programming C is like driving a fast and powerful car. Having learned to handle the car safely you would not willingly return to the family saloon. TJfhe hand-written format of this book has evolved over several years, and over six previous books on computers and programming languages. The pages contain the kind of diagram an able lecturer draws on the blackboard and annotates with encircled notes. Written text has been kept short and succinct. I have tried to avoid adverbs, cliches, jargon and unnecessarily formal language. IX hope the result looks friendly. QE1GATE Surrey, UK. February 1992 IX