Chapter 9  Inheritance

1. One of the keys to the power of OOP is achieving software reusability through 
   inheritance.

2. The programmer can designate that the new class is to inherit the data members 
   and member functions of a previously defined base class. In this case, the 
   new class is referred as a derived class.

3. A derived class normally adds data members and member functions of its own. so 
   a derived class generally has a larger definition than its base class. A 
   derived class is more specific than its base class and normally represents 
   fewer objects.

4. A derived class cannot access the private members of its base class; allowing 
   this would violate the encapsulation of the base class. A derived class can 
   however access the public and protected members of its base class.

5. Inheritance enables software reusability which saves time in development and 
   encourages the use of previously proven and debugged high-quality software.

6. Inheritance can be accomplished from existing class libraries.

7. Someday, most of software will be constructed from standardized reusable 
   components exactly as most hardware is constructed today.

8. The implementor of the derived class does not need access to the source code 
   of a base class, but does need the interface to the base class and the base 
   class's object code.

9. An inheritance hierarchy can be arbitrarily deep within the physical 
   limitations of a particular system.

10. Hierarchies are useful tools for understanding and managing complexity. With 
    software becoming increasingly complex, C++ provides mechanisms for supporting 
    hierarchical structures through inheritance and polymorphism.

11. Protected members of a base class may be accessed by members and friends of 
    the base class and by members and friends of derived classes; no other 
    functions can access the protected members of a base class.

12. Protected members are used to extend privileges to derived classes while 
    denying those privileges to non-class, non-friend functions.

13. When deriving a class from a private base class, public and protected members 
    of the base class become private members of the derived class.

14. When a base-class member is inappropriate for a derived class, we may simply 
    redefine that member in the derived class.

15. A base class specifies commonality. All classes derived from a base class 
    inherit the capabilities of that base class. In the OOD process, the designer 
    looks for commonality and factors it out to form desired base classes. 
    Derived classes are then customized beyond the capabilities inherited from 
    the base class.

16. Indicate multiple inheritance by following the colon (:) inheritance indicator 
    with a comma-separated list of the base class.

17. When performance is a major concern, programmers may want to see source code 
    of classes they are inheriting from so they can tune the code to meet their 
    performance requirements.

18. Inheritance from the class "closest" to what you need to save time and space.

19. A derived class can not directly access private members of its base class.