class Vector2D extends Vecteur {

  public Vector2D project(double direction) {
    // create the unit vector in direction angle
    if (direction >= Math.PI * 2)
      direction = direction - Math.PI * 2;
    Vector2D unitVect = new Vector2D(new Angle(direction), 1);
    double norm = this.prodScalaire(unitVect);
    return unitVect.changeNorm(norm);
  }

  public  Vector2D(double x, double y);
  public  Vector2D();
  public  Vector2D(IDirectPosition dp1, IDirectPosition dp2);
  public  Vector2D(IDirectPosition dp1);
  public  Vector2D(Angle angle, double norm);

}