Programs

A program in C consists of only function definitions and structure definitions.

Therefore a source file is simply a list of functions and types. These functions can call each other or themselves, and can use any data types that have been declared or are built into the language.

It is possible to call functions in other libraries, or to use their data types. This is how layers of complexity are accumulated in C programming.

As we saw in the previous chapter, the execution of a C program always starts in the function called main. From here it calls more and more functions, to perform all the actions it requires.