A friend is an entity to which a class grants access authority.
Friends can be functions, other classes, or individual member functions of other classes. Friend classes are used when two or more classes are designed to work together and need access to each other's implementation in ways that the rest of the world shouldn't be allowed to have. In other words, they help keep private things private. For instance, it may be desirable for class
DatabaseCursor to have more privilege to the internals of class
In the early days of OO, people had all ...