Deriving new classes

To change or add behavior to a class, you derive a new class from it:

class TNewWindow : public TWindow
{
 public:
  TNewWindow(...);
 // ...
};

When you derive a new class, you can do three things:

• Add new data members
• Add new member functions
• Override inherited member functions

Adding new members lets you add to or change the functionality of the base class. You can define a new constructor for your derived class to call the base classes' constructors and initialize any new data members you might have added.