pcl::Normal的定义及cout

     /*brief A point structure representing normal coordinates and the surface curvature estimate. (SSE friendly)ingroup common*/
    
    struct Normal : public _Normal
    {
    inline Normal (const _Normal &p)
    {
     normal_x = p.normal_x; 
     normal_y = p.normal_y; 
     normal_z = p.normal_z;
     data_n[3] = 0.0f;
     curvature = p.curvature;
    }
    
    inline Normal ()
    {
     normal_x = normal_y = normal_z = data_n[3] = 0.0f;
     curvature = 0;
    }
    
    inline Normal (float n_x, float n_y, float n_z)
    {
     normal_x = n_x; n