// Programmer: Austin Guthals
// Show that y=func(x)+z+func(x) is not always equal
// to y=2*func(x)+z
// my function will modify z 

#include <math.h>
#include <stdio.h>

void main()
{
	int *x, y1, y2, z;
	x=&z;
	z=0;  // initialize z to zero
	y1 = 2*func(x)+z;
	z=0;  // since z will be changed I must reset z to zero
	y2 = func(x)+z+func(x); // Although z is changed, it doesn't
// affect the final value because z is used before func(x) is called a
//second time. func(x) will return a different value the second time
	printf("2*func(x) + z = ");
	printf("%d", y1);
	printf("\n");
	printf("func(x) + z + func(x) = ");
	printf("%d", y2);
	printf("\n");

}


int func(int *q)
{
	int h;
	h = 2+(*q);
	*q = *q + 4;
	return h;
}