/*****************************************************************
 * File: Point2d.java
 * Synopsis:
 *      Basic Point Class for 2-dimensional geometry
 *
 * $Id: Point2d.j,v 1.1 2003/02/12 17:57:36 yap Exp $
 *****************************************************************/

class Point2d extends GeomObj {

public:
  double x, y;
 
  //Constructors
  Point2d();  //initialized to origin(0,0)
  Point2d(double, double);
  Point2d( Point2d );
  Point2d(Vector v);
  //create a point initialized to the point $(v[0], v[1])$ 
  //precondition: v.dim() = 2

  //destructor
  virtual ~Point2d() {}

  Point2d operator=( Point2d);
  
  double X()  { return x; }
  double Y()  { return y; } 

  double distance( Point2d) ;
  // returns the Euclidean distance between p and this

  double distance()  { return distance(Point2d(0, 0)); }
  // returns distance between this and origin

  Point2d operator+( Point2d ) ;
  Point2d operator-( Point2d ) ;

  Point2d rotate90(  Point2d q);
  // returns the point rotated about q by angle of 90 degrees

  bool operator==( Point2d) ;
  bool operator!=( Point2d p)  {return !operator==(p); }
  
  void dump(String m);
  // write point p to output stream, printing message m
  void dump();
  // dump without message

  void read();
  // reads the x and y coordinates of point p from standard input 

};


// OTHER:
Point2d center(Point2d a, Point2d b); 
int orientation2d( Point2d a,  Point2d b,  Point2d c);
double area( Point2d a,  Point2d b,  Point2d c);
bool collinear( Point2d a,  Point2d b,  Point2d c);