Something

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);
 }
};