Example of Abstract Classes
class KeyPressHandler { // specification for key press event handlerpublic: virtual void keyDown (char c) = 0;
class MouseDownHandler { // specification for mouse down event handlerpublic: virtual void mouseDown (int x, int y) = 0; virtual void mouseUp (int x, int y) = 0;
class EventHandler : public KeyPressHandler, public MouseDownHandler {public: void keyDown (char c) { ... } void mouseDown (int x, int y) { ... } void mouseUp (int x, int y)( { ... }