The book by a well-known specialist and lecturer in the field of computer technology is devoted to the latest standard (C99) of one of the most common programming languages - C, which served as the basis for the creation of the Unix operating system. The book features a simple and accessible style of presentation, an abundance of examples and many recommendations for writing high-quality programs. Such issues as the representation of data in the C language, operations and operators, control structures and functions are considered in detail. Considerable attention is paid to string processing, I / O, working with arrays and structures, and memory management issues. Comprehensive information about the preprocessor and standard library functions will enable you to efficiently create program code. The questions for self-control and exercises for self-study given at the end of each chapter will allow you to securely consolidate your knowledge.The book is designed for programmers of various qualifications, and will also be useful for students and teachers of disciplines related to programming.