Chapt 8. Basic object-oriented programming

8.13 Friend functions and classes: (Learn C++)

friend function: function that can access private member of the class

friend class: if class A is friend of B, then B can access private member object A’s

∗ ‘friend’ must be declared inside of class, but in can be private or public section

∗ friend functions is not, rigorously, member of the class

∗ friend relationship is asymmetric, not symmetric