Question

When is a friend function compulsory? give an example?

Answer 1

n that case, the functions don't need to be declared as friends of the class, because they don't need access to private members. But these functions typically need to access at least one private member, so to gain that access, they need to be declared as friends of the class.

Answer 2

In that case, the functions don't need to be declared as friends of the class, because they don't need access to private members. But these functions typically need to access at least one private member, so to gain that access, they need to be declared as friends of the class.