Introduction to OOP Chapter 8: Inheritance and Substitution: next previous audio real text

Syntax for Overriding

Some languages, such as C++, require that the programmer indicate in the parent class that overriding is a potential:

	class GraphicalObject {
		virtual void draw();  // can be overridden

Other languages, such as Object Pascal, require a modifier in the child class that overriding has taken place:
	Ball = object (GraphicalObject)
		procedure draw; override; (* overriding has taken place *)
Still other languages (C#, Delphi) require indications in both parent and child.
And some languages (Smalltalk) do not require any indication in either parent class or child class.
Intro OOP, Chapter 8, Slide 13