GradeBook Class Definition
GradeBook’s class definition (Fig. 3.15)—and hence, its interface—is identical to that of Fig. 3.11. Since the interface remains unchanged, clients of this class need not be changed when the definition of member function
setCourseName is modified. This enables clients to take advantage of the improved
GradeBook class simply by linking the client code to the updated
GradeBook’s object code.