Сравнение длины двух векторов

class Vector
{
    float x, y, z;
public:
    Vector();
    Vector(const Vector&a);
    Vector(float mx, float my, float mz);
    Vector&operator=(const Vector&a);
    Vector&operator+(const Vector&a)const;
    Vector&operator-(const Vector&a)const;
    Vector&operator*(float a)const;
    Vector&operator*(const Vector&a)const;
    inline float Magnitude();
    
    void show();
    void showMag();
    ~Vector();
};
 bool operator<(const Vector&lhs,const Vector&rhs);
 bool operator>(const Vector&lhs, const Vector&rhs);
 
/*.......*/ implementation
 
Vector & Vector::operator*(const Vector & a) const
{
    return Vector(x*a.x, y*a.y, z*a.z);
}
 
inline float Vector::Magnitude()
{
    
    return sqrt(x*x+y*y + z*z);
}
 
 
void Vector::show()
{
    cout << x << " " << y << " " << z;
}
 
void Vector::showMag()
{
    cout << Magnitude();
}
 
Vector::~Vector()
{
}
 
 bool operator<(const Vector & lhs, const Vector & rhs)
{
    return (lhs < rhs);
}
 
bool operator>(const Vector & lhs, const Vector & rhs)
{
    return lhs > rhs;
}
 
 
int main()
 
cout << "\nMagnitude vector1\n";
    ob1.Magnitude();
    ob1.showMag();
    cout << "\nMagnitude vector2\n";
    ob2.Magnitude();
    ob2.showMag();
 
????????

bool operator<(const Vector & lhs, const Vector & rhs)
{
    return lhs.Magnitude() < rhs.Magnitude();
}