int a;

int add (int a, int b, int * result)
{
    int c;

    {
	int a;

	a = 3;

	c = a+b;

	printf ("c = %d\n", c);
    }

    c = a+b;

    *result = c;

    return (c);
}

int res = 7;

a = add (4,5, &res);

printf ("a = %d, %d (%d)\n", a, res, 4+5);