Sales_data class defined three ordinary nonmember functions as friends (§ 7.2.1, p. 269). A class can also make another class its friend or it can declare specific member functions of another (previously defined) class as friends. In addition, a friend function can be defined inside the class body. Such functions are implicitly
As an example of class friendship, our
Window_mgr class (§ 7.3.1, p. 274) will have members that will need access to the internal data of the
Screen objects it manages. For example, let’s assume that we want to add a member, named
Window_mgr that will reset the contents of a particular
Screen to all blanks. To do this job,
clear needs to access ...