namespace algebra {

    class Vector:public Object {

      public:

        enum Mode { DEG, RAD, GRAD };

        Vector (int xx = 0, int yy = 0);

        virtual ~ Vector ();

        int X ();

        int Y ();

        Vector operator+ (Vector &);

        Vector operator- (Vector &);

        double abs ();

        void vector ();

        double angle (Vector &);

        void setMode (Mode m = RAD);

      private:

        Mode mode;

        int x;

        int y;

    };

}