CALL BY REFERENCE

 #include<iostream>

using namespace std;

void swap(int &a,int &b)

{

    cout<<&a<<" "<<&b;

    int temp;

    temp=a;

    a=b;

    b=temp;

}

int main()

{

    int x=10; int y=20;

    swap(x,y);

    cout<<&x<<" "<<&y<<endl;

    cout<<x<<" "<<y<<endl;

}