class KlasaGlowna { public: virtual void printMessage () = 0; }; class SubKlasa1: public KlasaGlowna { public: virtual void printMessage (void) { MessageBox(NULL, "This is a Company Confidential Resource...", "-", 1); } }; class SubKlasa2 : public KlasaGlowna { public: virtual void printMessage (void) { MessageBox(NULL, "This is a Public Resource...", "-", 1); } };