include preprocessor.

The include preprocessor will add source code to your existing source. This is used to include header files that contain function declarations. For example:

	#include <stdio.h>
	main()
	printf("hi peeps");
	}

The printf function declaration is held in stdio.h

There are two ways of defining the include files location.

<>says to the preprocessor that the file is in the system libraries.
```
	#include <stdio.h>
```
""means that this is a user defined file. Absolute or relative paths may be defined.
```
	#include "myheaders.h"
	#include "/usr/home/leslim/myheaders.h"
```