#include<iostream>                                                               
using namespace std;                                                             
                                                                                 
void swap(int *x, int *y)                                                        
{                                                                                
    int *tmp = x;                                                                
    x = y;                                                                       
    y = tmp;                                                                     
}                                                                                
                                                                                 
int main()                                                                       
{                                                                                
    int u = 10;                                                                  
    int v = 20;                                                                  
    int * p = &u;                                                                
    int * q = &v;                                                                
    swap(*p, *q);                                                                
    std::cout<<"u :-"<<u<<" v  :-"<<v<<endl;                                     
    return 0;                                                                    
}