troca!

troca.c

#include <stdio.h>

void troca(int *x, int *y);

int main(void) {
  
  int x, y;

  x = 10;
  y = 20;

  troca(&x, &y);
  printf("X: %d\n", x);
  printf("Y: %d\n", y);

  return 0;
}

void troca(int *x, int *y) {
  int aux;
  aux = *y;
  *y = *x;
  *x = aux;
}