41: Exemple

template < class FT >
Orientation
orientation (const FT &px, const FT &py,
             const FT &qx, const FT &qy,
             const FT &rx, const FT &ry)
{
  FT d1 = (px-qx)*(qy-ry);
  FT d2 = (py-qy)*(qx-rx);
  if (d1 < d2) return RIGHTTURN;
  if (d1 > d2) return LEFTTURN;
  return COLLINEAR;
}