#include <stdio.h>

void swap(int *a, int *b)
{
	int tmp;

	tmp = *a;
	*a = *b;
	*b = tmp;
}

int main(void)
{
	int x = 4, y = 5;

	printf("x=%d, y=%d \n", x, y);
	swap(&x, &y);
	printf("x=%d, y=%d \n", x, y);
}