#include <iostream>
using namespace std;
class BB;
class AA
{
int a1;
public:
void getdata(int l)
{
    a1=l;
}
void display()
{
    cout<<"the value of a is"<<a1<<endl;
}
friend void swap(AA &a,BB &b);
};
class BB
{
int b1;
public:
void getdata(int m)
{
    b1=m;
}
void display()
{
    cout<<"the value of b is"<<b1<<endl;
}
friend void swap(AA &a,BB &b);
};
void swap(AA &a,BB &b)
{
    int temp;
    temp=a.a1;
    a.a1=b.b1;
    b.b1=temp;
}
int main()
{
    AA a;
    BB b;
    a.getdata(10);
    b.getdata(20);
    a.display();
    b.display();
    swap(a,b);
    a.display();
    b.display();
    return 0;
}