#include <stdio.h>


void swap(int **x, int **y) {

  int* t = *x;
  *x = *y;
  *y = t;
}

 
void print_int_array(char* name, int* array, int size){

  int i;

  printf("%s:", name);
  for(i= 0; i<size; i++)
    printf(" %i", array[i]);
  printf("\n");
}
   
int main(){
  
  int a[]= {1, 2, 3, 4};
  int b[]= {5, 6, 7, 8};
  
  int *pa;
  pa = &a[0]; 

  int *pb;
  pb = &b[0];
  
  print_int_array("a", pa, 4);
  print_int_array("b", pb, 4);

  swap((void*)&pa, (void*)&pb);

  print_int_array("a", pa, 4);
  print_int_array("b", pb, 4);
}