#include<stdio.h>
void swap(int *, int *);
int main()
{
   int x=15,y=42;
   printf("x = %d, y = %d\n",x,y);
   swap(&x,&y);
   printf("x = %d, y = %d\n",x,y);
}
void swap(int *a, int *b)
{
   int temp;
   temp = *a;
   *a = *b;
   *b = temp;
}