This chapter concludes our coverage of the C programming language. Compared to other high-level programming languages, C is a relatively small programming language with a few basic constructs from which a programmer builds their program. Because C language abstractions are closer to the underlying machine code executed by the computer, a C programmer can write code that runs much more efficiently than equivalent code written using the higher-level abstractions provided by other programming languages. In particular, a C programmer has much more control over how their program uses memory, which can have a significant impact on the program’s performance. C is the language of computer systems programming where low-level control and efficiency are crucial.

In subsequent chapters we use C examples to illustrate how a computer system is designed to run a program.