#include<stdio.h>
void swap(int*,int*);
void main()
{  int a,b,*p1,*p2;
   a=10;b=20;p1=&a;p2=&b;
   printf("a=%d,b=%d\n",a,b);
   swap(p1,p2);
   printf("a=%d,b=%d\n",a,b);
}
void swap(int*pa,int*pb)
{  int temp=*pa;
   *pa=*pb;
   *pb=temp;
}