C Programming Language

Brian W. Kernighanworks in the Computing Science Research Center at Bell Laboratories, Lucent Technologies. He is Consulting Editor for Addison-Wesley's Professional Computing Series and the author, with Dennis Ritchie, ofThe C Programming Language.

Dennis Ritchieis a computer scientist notable for his influence on<A title=ALTRAN href="http:///wiki/ALTRAN">ALTRAN</A>,<A title="B more >>

Brian W. Kernighanworks in the Computing Science Research Center at Bell Laboratories, Lucent Technologies. He is Consulting Editor for Addison-Wesley's Professional Computing Series and the author, with Dennis Ritchie, ofThe C Programming Language.

Dennis Ritchieis a computer scientist notable for his influence onALTRAN,B,BCPL,C,Multics, andUnix.

This book is meant to help the reader learn how to program in C. It is the definitive reference guide, now in a second edition. Although the first edition was written in 1978, it continues to be a worldwide best-seller. This second edition brings the classic original up to date to include the ANSI standard.

From the Preface:

We have tried to retain the brevity of the first edition. C is not a big language, and it is not well served by a big book. We have improved the exposition of critical features, such as pointers, that are central to C programming. We have refined the original examples, and have added new examples in several chapters. For instance, the treatment of complicated declarations is augmented by programs that convert declarations into words and vice versa. As before, all examples have been tested directly from the text, which is in machine-readable form.

As we said in the first preface to the first edition, C "wears well as one's experience with it grows." With a decade more experience, we still feel that way. We hope that this book will help you to learn C and use it well.

Preface

The computing world has undergone a revolution since the publication ofThe C Programming Languagein 1978. Big computers are much bigger, and personal computers have capabilities that rival the mainframes of a decade ago. During this time, C has changed too, although only modestly, and it has spread far beyond its origins as the language of the UNIX operating system.

The growing popularity of C, the changes in the language over the years, and the creation of compilers by groups not involved in its design, combined to demonstrate a need for a more precise and more contemporary definition of the language than the First edition of this book provided. In 1983, the American National Standards Institute (ANSI) established a committee whose goal was to produce "an unambiguous and machine-independent definition of the language C," while still retaining its spirit. The result is the ANSI standard for C.

The standard formalizes constructions that were hinted at but not described in the first edition, particularly structure assignment and enumerations. It provides a new form of function declaration that permits cross-checking of defini-tion with use. It specifies a standard library, with an extensive set of functions for performing input and output, memory management, string manipulation, and similar tasks. It makes precise the behavior of features that were not spelled out in the original definition, and at the same time states explicitly which aspects of the language remain machine-dependent.

This second edition ofThe C Programming Languagedescribes C as defined by the ANSI standard. Although we have noted the places where the language has evolved, we have chosen to write exclusively in the new form. For the most part, this makes no significant difference; the most visible change is the new form of function declaration and definition. Modern compilers already support most featu << less