#include <stdio.h>

void nao_troca(int x, int y) {
  int aux;

  aux = x;
  x = y;
  y = aux;
}


void troca(int *ap_x, int *ap_y) {
  int aux;

  aux = *ap_x;
  *ap_x = *ap_y;
  *ap_y = aux;
}

int main() {
  int x = 100, y = 200;

  nao_troca(x, y);
  printf("x = %d, y = %d\n", x, y);

  troca(&x, &y);
  printf("x = %d, y = %d\n", x, y);
  
  return 0;
}