Program #1
#include <stdio.h>

int sum(int,int);

void main(void)
{
	int a=10,b=50,c;
	c=sum(a,b);
        	printf("a=%d, b=%d & c=%d", a, b, c);
}


int sum(int a, int b)
{
	int value;
	value=a+b;
        	return(value);
}

Program #2
#include <stdio.h>

int sum(int,int);

void main(void)
{
	int a=10,b=50,c;
	c=sum(a,b);
        	printf("a=%d, b=%d & c=%d", a, b, c);
}


int sum(int a, int b)
{
	int value;
	a=1;
        	b=2;
	value=a+b;
        	return(value);