The book is organized as follows. Chapter 1 is a tutorial on the central part of C. The purpose is to get the
reader started as quickly as possible, since we believe strongly that the way to learn a new language is to write
programs in it. The tutorial does assume a working knowledge of the basic elements of programming; there is
no explanation of computers, of compilation, nor of the meaning of an expression like n=n+1. Although we
have tried where possible to show useful programming techniques, the book is not intended to be a reference
work on data structures and algorithms; when forced to make a choice, we have concentrated on the language.
Chapters 2 through 6 discuss various aspects of C in more detail, and rather more formally, than does Chapter
1, although the emphasis is still on examples of complete programs, rather than isolated fragments. Chapter 2
deals with the basic data types, operators and expressions. Chapter 3 threats control flow: if−else,
switch, while, for, etc. Chapter 4 covers functions and program structure − external variables, scope
rules, multiple source files, and so on − and also touches on the preprocessor. Chapter 5 discusses pointers and
address arithmetic. Chapter 6 covers structures and unions.
Chapter 7 describes the standard library, which provides a common interface to the operating system. This
library is defined by the ANSI standard and is meant to be supported on all machines that support C, so
programs that use it for input, output, and other operating system access can be moved from one system to
another without change.
Chapter 8 describes an interface between C programs and the UNIX operating system, concentrating on
input/output, the file system, and storage allocation. Although some of this chapter is specific to UNIX
systems, programmers who use other systems should still find useful material here, including some insight
into how one version of the standard library is implemented, and suggestions on portability.
Appendix A contains a language reference manual. The official statement of the syntax and semantics of the C
language is the ANSI standard itself. That document, however, is intended foremost for compiler writers. The
reference manual here conveys the definition of the language more concisely and without the same legalistic
style. Appendix B is a summary of the standard library, again for users rather than implementers. Appendix C
is a short summary of changes from the original language. In cases of doubt, however, the standard and one's
own compiler remain the final authorities on the language.
