Can any one explain

Question

What is the problem in this program
https://code.sololearn.com/ci8lyVidN3lh/?ref=app

Answer 1

The friend function has to be a free function, you have to define it outside.

So you have to erase that B:: and it works.

void fun(A a,B b)
{
a.s=10;
cout<<"the s value is "<<a.s;
}

Answer 2

https://code.sololearn.com/cPINlV5ny8Id/?ref=app