C Custom Header File

You can create your custom header file in C; It helps you to manage user-defined methods, global variables, and structures in a separate file, which you can use in different modules.

A Process to Create Custom Header File in C

For example, in the following code, I am calling an external function named swap in my main.c file.

Example:

#include<stdio.h>
#include"swap.h"

void main()
{
    int a=20;
    int b=30;
    swap (&a,&b);
    printf ("a=%d\n", a);
    printf ("b=%d\n",b);
}

The swap method is defined in the swap.h file is used to swap two numbers using a temporary variable.

Example:

void swap (int* a, int* b)
{
    int tmp;
    tmp = *a;
    *a = *b;
    *b = tmp;
}