Un paramètre pour Avancer() ou non? (nombre de positions)
Anyway:

public class Robot
{
          int orientation;
          int abs, ords;
          

          public Robot(int _orientation, int _abs, int _ords)
          {
                 orientation = _orientation;
                 abs = _abs;
                 ords = _ords;
           }


           public void Avancer()
           {

               switch(oriantation)
               {
                case 1:
                      abs++;
                      break;

                case 2:
                      ords++;
                      break;

                case 3:
                      abs--;
                      break;

                case 4:
                      ords--;
                      break;  
                }
           }

           public vois Tourner(int nouvelleOrientation)
           {
                orientation = nouvelleOrientation;
            }

            public void Afficher()
            {
                  System.out.println("Orientation:" + orientation + "\nPosition: (" + abs + "," + ords + ")");
            } 




}