// file line3d.hpp

class Point {
 float x, y;
 public:
   void  SetCoords(float xx, float yy);
   float GetCoordX();
   float GetCoordY();
};

class Point3d: public Point {
 float z;
 public:
   void  SetCoords(float xx, float yy, float zz);
   float GetCoordZ();
};

class Line {
 Point A, B;
 float dx, dy;
 public:
   void SetExtremes(float ax, float ay, float bx, float by);
   float GetLength();
};

class Line3d {
 Point3d A, B;
 float dx, dy, dz;
 public:
   void SetExtremes(float ax, float ay, float az, float bx, float by, float bz);
   float GetLength();
};

// end of file line3d.hpp