I/O Manipulators with Parameters - 3

// manipulator for setting width
class SetWidth
{
  public:
    SetWidth(int width) : width_(width)
    {}
    void operator() (std::ios_base& s)
    {
      s.width(width_);
    }
  private:
    int width_;
};

// useage:
os << SetWidth(8) <<  x;
is >> SetWidth(8) >>  y;