My own header files

Hi!

My question is how to make my own header files? I' m writing a program and I want that every function will be in his own .c file. Something like this:
main.c
main.h
about.c
about.h
...

I was trying something but I always get a lot of errors .

Please help.

Don't know if you have tried this already >

Create the header file, say example.h, using
#ifndef EXAMPLE_H
#define EXAMPLE_H

at the beginning

and
#endif

at the end


call the header file then from your main file using

#include "example.h"

Your main.c file has to include all the headers of the functions you are trying to use.

> I was trying something but I always get a lot of errors
Yeah, posting them would have been a big help

Unless you want another 20 messages guessing...

create afile main.h
write there your function

then create your main.c
write there your program
and at the top write

#include "main.h"

My main.c file:

Code:

# include "main.h"

int main()
{
// few functions and they are defined in main.h
}

main.h file:

Code:

# include <windows.h>
# include <stdio.h>
# include <conio.h>
# include <string.h>

# define LEFT_CTRL  40
# define LEFT_ALT   34
# define RIGHT_ALT  33
# define RIGHT_CTRL 36

void clrscr (void);

void clrscr ()
{
  system ("CLS");
}

about.c file:

Code:

# include "main.h"
# include "about.h"

void About ()
{
 // code
}

about.h file:

Code:

void About (void);

These are my 4 files. I get an error that function clrscr () is already defined in main.obj.

Code:

void clrscr ()
{
  system ("CLS");
}

Move this to main.c

Is there no way to have a clrscr in a main.h file? And for the # define I too get errors that they are already defined in main.obj file. Should I moved them too into main.c file?

void clrscr (void);
This in the .h file

void clrscr ()
{
system ("CLS");
}
This in the .c file

Declarations (#defines, prototypes etc) go in .h files

Definitions go in .c files

You managed it with your about function.


All .h files should begin with
#ifndef FILE_INCLUDED
#define FILE_INCLUDED

And end with
#endif

Eg

Code:

#ifndef MAIN_H
#define MAIN_H
# include <windows.h>
# include <stdio.h>
# include <conio.h>
# include <string.h>

# define LEFT_CTRL  40
# define LEFT_ALT   34
# define RIGHT_ALT  33
# define RIGHT_CTRL 36

void clrscr (void);
#endif MAIN_H

This protects you from including the same .h file several times

One more question. What about constants (const int x = 5?

extern const int x;
Would go in a .h file


const int x = 5;
would go in a .c file

Is there anything else that I should know about the header files?