C++ program to call by reference

Program -

#include<iostream.h>

#include<conio.h>

 void main()

{

clrscr();

int x,y,*p1,*p2;

void exchange(int,int);

cout<<"\n enter the value of x and y:";

cin>>x>>y;

p1=&x;

p2=&y;

cout<<"\n before exchange x="<<x<<"and y="<<y<<endl;

exchange(p1,p2);

cout<<"\n after the exchange x="<<*p1<<"and y="<<*p2;

getche();

}

void exchange(int*p3,int*p4)

{

int temp1;

temp1=*p3;

*p3=*p4;

*p4=temp1;

return;

}

Output - 

enter the value of x and y: 5    10

before exchange x=5and y=10

after exchange x=10 and y =5