#include<iostream.h>
class data2;
class data1
{
    int a;
    public:
    void get(int no)
    {
        a=no;
    }
    friend void swap(data1 &, data2 &);
    void show()
    {
        cout<<"a= "<<a<<endl;
    }
};

class data2
{
    int b;
    public:
    void get(int no)
    {
        b=no;
    }
    friend void swap(data1 &,data2 &);
    void show()
    {
        cout<<"b= "<<b<<endl;
    }
};
void swap(data1 &a1,data2 &a2)
{
    int temp;
    temp=a1.a;
    a1.a=a2.b;
    a2.b=temp;
}

main()
{
    data1 a;
    data2 b;
    a.get(10);
    b.get(20);
    cout<<"\n\n Before swapping \n\n";
    a.show();
    b.show();
    swap(a,b);
    cout<<"\n\n After swapping\n\n";
    a.show();
    b.show();
}