... This file is new. It contains the definition of the GameBoard class, which was last seen as MyWidget. class GameBoard : public QWidget { Q_OBJECT public: GameBoard( QWidget *parent=0, const char *name=0 ); protected: void resizeEvent( QResizeEvent * ); protected slots: void fire(); void hit(); void missed(); void newGame(); private: QPushButton *quit; QPushButton *shoot; QPushButton *restart; LCDRange *angle; LCDRange *force; QLCDNumber *hits; QLCDNumber *shotsLeft; CannonField *cannonField; }; . ...