#include <stdio.h>

void swap(int *p_a, int *p_b) {
	int aux;
	printf("swap: a=%d @%p, b=%d @%p\n", *p_a, p_a, *p_b, p_b);
	aux=*p_a;
	*p_a=*p_b;
	*p_b=aux;
	printf("swap: a=%d @%p, b=%d @%p\n", *p_a, p_a, *p_b, p_b);
}

main() {
	int a=5, b=7;
	printf("main: a=%d @%p, b=%d @%p\n", a, &a, b, &b);
	swap(&a,&b);
	printf("main: a=%d @%p, b=%d @%p\n", a, &a, b, &b);
}