#include <stdio.h>

void swap(char **, char**);
void swap_int(int *, int *);

int main(void){
  char *s1 = "Hola";
  char *s2 = "Mundo";
  int n1 = 10;
  int n2 = 20;
  swap(&s1, &s2);
  swap_int(&n1, &n2);
  printf("s1: %s s2: %s\n", s1, s2);
  printf("n1: %d n2: %d\n", n1, n2);
  return 0;
}

void swap(char **s1, char **s2){
  char *aux = *s1;
  *s1 = *s2;
  *s2 = aux;
}

void swap_int(int* n1, int* n2){
  int aux = *n1;
  *n1 = *n2;
  *n2 = aux;
}