How to use friend function to two different classes

Question

when I try to use friend function to two different classes in turbo c in c++ it's showing error what's the problem
how can I use it . is it possible?

Answer 1

what's the error shown?

Answer 2

When using a friend function you need to pass the objects of the classes in the parameters.

Answer 3

I can't understand the problem but if two classes should use a friend function how plZzz help me