Method showVolume

Examples/NoModules/Chapter 15/Ex15_08/Box.h:21–25

  virtual double volume() const { return m_length * m_width * m_height; }

  void showVolume() const
  {
    std::cout << "The volume from inside Box::showVolume() is "
              << volume() << std::endl;
  }

private:
  double m_length, m_width, m_height;