class Position
{
  float x,y;
  
  Position() {}
  Position(float tx,float ty)
  {
    x = tx;
    y = ty;
  }
  Position(Position p)
  {
    if (p != null) {
      x = p.x;
      y = p.y;
    }
  }
  
  void add(Vector v)
  {
    x += cos(v.a)*v.m;
    y += sin(v.a)*v.m;
  }
  
  void set(float tx,float ty)
  {
    x = tx;
    y = ty;
  }  
  void set(Position p)
  {
    x = p.x;
    y = p.y;
  }
  
  boolean on_screen()
  {
    return (x >= 0 && x <= width && y >= 0 && y <= height);
  }
  
  boolean equals(Position p)
  {
    return x == p.x && y == p.y;
  }
}

float dist(Position $1, Position $2)
{
  return dist($1.x, $1.y, $2.x, $2.y);
}
float atan2(Position $1, Position $2)
{
  return atan2($2.y - $1.y, $2.x - $1.x);
}