View -- for display
class V : virtual public A {\fbox{V}
public: V( int h, int w ) : d(new Display(h,w)) { } void display() { d->put( value() ); } private: Display* d; };
class V : virtual public A {\fbox{V}
public: V( int h, int w ) : d(new Display(h,w)) { } void display() { d->put( value() ); } private: Display* d; };