#include<stdio.h>
void cambiar(int *a, int *b);

int main ()
{
    int p;
    int q;
    int *p,*q;
    int x,y;

    p = &x;
    q = &y;

    cambiar(p,q);

    system ("PAUSE");
    return 0;
}

void cambiar(int *a, int *b)
{

int aux = *p;

*p = *q;
*q = aux;
}