text: #ifndef GEOMETRY_LINESEGMENT_H
  #define GEOMETRY_LINESEGMENT_H
  #include "point.h"
  #include "linearobj.h"
  
  class LineSegment : public LinearObject
  {
          public:
                  LineSegment(const Point& p1, const Point& p2);
                  double GetLength() const;
                  virtual bool IsOn(const Point&) const;
  };
  
  #endif