Book excerpt: C is the programming language of choice when speed and reliability are required. It is used for many low-level tasks, such as device drivers and operating-system programming. For example, much of Windows and Linux is based on C programming. The updated 4th edition of Beginning C builds on the strengths of its predecessors to offer an essential guide for anyone who wants to learn C or desires a ‘brush-up’ in this compact, fundamental language. This classic from author, lecturer and respected academic Ivor Horton is the essential guide for anyone looking to learn the C language from the ground up.