Перегруженный оператор вывода

class CPoint
{
    friend std::istream &operator>>(std::istream &in, CPoint &point);
    friend std::ostream &operator<<(std::ostream &out, const CPoint &point);
 
public:
    CPoint(double x=0.0, double y=0.0);
    ~CPoint();
    void SetX(double x);
    void SetY(double y);
    void SetPoint(double x, double y);
    double GetX() const;
    double GetY() const;
 
protected:
    double mX, mY;
};
 
 
 
 
 
class CCircle : public CPoint
{
    friend std::istream &operator>>(std::istream &in, CCircle &circle);
    friend std::ostream &operator<<(std::ostream &out, const CCircle &circle);
 
public:
    CCircle(double x=0.0, double y=0.0, double radius=1.0);
    ~CCircle();
    void SetRadius(double radius);
    double GetRadius() const;
    double GetArea() const;
 
protected:
    double mRadius;
};
 
 
 
 
 
class CCylinder : public CCircle
{
    friend std::istream &operator>>(std::istream &in, CCylinder &cylinder);
    friend std::ostream &operator<<(std::ostream &out, const CCylinder &cylinder);
 
public:
    CCylinder(double x=0.0, double y=0.0, double radius=1.0, double height=1.0);
    ~CCylinder();
    void SetHeight(double height);
    double GetHeight() const;
    double GetArea() const;
    double GetVolume() const;
 
protected:
    double mHeight;
};