1.2.1 Design
   1.2.1.1 class categories
   1.2.1.2 relationships between classes
   1.2.1.3 Has-a relationship
   1.2.1.4 Is-a relationship
   1.2.1.5 virtual function and override
   1.2.1.6 MI or bridge
  1.2.2 Interface
  1.2.3 Special member functions
   1.2.3.1 Basic
   1.2.3.2 Rules of implicitly declare
   1.2.3.3 initializer list
   1.2.3.4 Basic routines
  1.2.4 special member functions in inheritance
   1.2.4.1 ctor
   1.2.4.2 destructor
   1.2.4.3 copy ctor
  1.2.5 RAII