Making your own header files

[42hU7k9E]

I need a good explanation about making header files, and should be explained werry nice and understandable.

Thank you, kajzec

[helios]

Can you be a little more specific?

[42hU7k9E]

I was thinking of a header, that had a function for addition, multyplying etc. Is that even possible?

[helios]

Headers usually contain:
* An inclusion guard to prevent errors.
* Inclusion of other headers that contain declarations that the ones in it require (for example, a header that declares a function that returns an std::string would #include <string>).
* Declarations necessary by all files that include it.

Following my previous example, a header could look like this:

//Necessary inclusions:
#include <string>

//Inclusion guard. It will prevent the same header from being included twice in
//the same file:
#ifndef EXAMPLE_H
#define EXAMPLE_H

//Definitions:
std::string some_function();
#endif