The following example shows the pattern of the final exam. You have to
write the required header file containing necessary function(s).

--------------------------------------------------------------------------
Write a header file to implement a function to add two numbers using 
a function named add(). It should work with main program as shown below:

$ cat main.c
#include <stdio.h>
#include "iit2013456_1.h"

int main()
{
	int i;
	int j;

	scanf("%d", &i);
	scanf("%d", &j);
	printf("%d\n", add);

	return 0;
}
$ cat iit2013456_1.h
int add(int x, int y)
{
	int z;

	z = x + y;

	return z;
}
$ cc main.c
$ ./a.out
5 6
11
$