Effective C + + clause VII declaring a virtual destructor for a polymorphic base class

class Timekeeper

  {

  Public:

      Timekeeper ();

     ~timekeeper (); Error, which is inherited as a base class. The base class is destroyed after its inherited class is deleted, but the inheriting class may not be destroyed

      virtual ~timekeeper (); //must be declared as virtual type only. 

  protected:

  Private:

  };

  class  Public //Inheritance

  timekeeper* PTK = Gettimekeeper ();

  Delete PTK;

Remember:

1. A base class with polymorphic properties should be declared as a virtual destructor, and if class has any virtual functions, he should have a virtual destructor.

2. The purpose of classes design if it is not used as a base class, or is not intended for polymorphism, it should not be declared as a destructor of type virtual.