OOP

OOP

1. virtual

   • destructor
     • if not there derived class dtor won't be called memory leak
   • constructor
     • theoretically not possible feasible thru Factory model
   • table
     • vptr added to base class
     • setup at compile time
     • supported even for classes with virtual base class

2. initializer list

   • first base then derived
   • reference data member
   • more efficient

3. template

   • partially specialized
   • fully specialized
   • templatized class / Func

4. ctor dtor

   • 1. ctor of most derived class to call ctor of virtual base class
   • 2. ctor in same order as defined
   • 3. non-static member of most derived classes in same order
   • 4. body of ctor executed
   • if ctor overloaded in derived then rest ctor hidden

5. operator new delete

   • new operator = op new + invoke ctor
   • op delete will be invoked by system if op new Ok but ctor NG

6. smart ptr

7. functor

   • class which define op()
   • they can contain state

8. object slicing

   • obj derived class = obj base class
   • data added by subclass discarded
   • obj of subclass is passed or returned by value from a function expecting base class obj

9. type casting

   • static
     • implicit
     • explicit
       • cast through inheritance hierarchy
   • dynamic
     • polymorphism
       • can cast sideways & up another chain
     • limitation
       • fail to travel thru protected/private inheritance
   • reinterpret
     • bit manupulation