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"
```

The main difference between the syntax of the two items is that if filename is enclosed in angled brackets, then the compiler searches for it somehow. If it is enclosed in quotes, then the compiler doesn't search very hard for the file.

While the behavior of these two searches is up to the compiler, usually the angled brackets means to search through the standard library directories, while the quotes indicate a search in the current directory. The spiffy new C++ #include commands don't need to map directly to filenames, at least not for the standard libraries. That's why you can get away with

  #include <iostream>

and not have the compiler choke on you.

Martin Leslie