Inheritance & Composition(Chapter 14 of Thinking in C++)

　　Inheritance and static member functions static member functions act the same as non-static member functions:

　　1. They inherit into the derived class.

　　2. If you redefine a static member, all the other overloaded functions in the base class are hidden.

　　3. If you change the signature of a function in the base class, all the base class versions with that function name are hidden (this is really a variation of the previous point).