/* variable scope and functions in C */

#include<stdio.h>

int summ_it(int var1, int var2);

int main()
{

	int a, b, c;

	a = 5;
	b = 7;

	c = summ_it(a, b);

	printf("%d plus %d equals %d\n", a, b, c);

}

int summ_it(int var1, int var2)
{
	int answer;

	answer = var1 + var2;

	/* this won't work, since 'a' exists only in
		the main function, and was not passed
		as the name 'a' to summ_it  */
	printf("variable a is %d\n", a);

	return answer;
}