public class Rooms
{
  public static void carpetRooms()
  {
    carpetRoom();
    carpetRoom();
    carpetRoom();
    carpetRoom();
    carpetRoom();
    carpetRoom();
    carpetRoom();
    carpetRoom();
  }
  
  // before: facing east, bottom row,
  //         in square before a possible room location
  // after:  facing east, bottom row,
  //         in square after a possible room location
  //         (i.e. in square before next possible
  //          room location)
  public static void carpetRoom()
  {
   // 1. enter room
    Rooms.enterRoom();
   // 2. if surrounded by walls, make it dark (carpet it)
    if ( Rooms.surroundedByWalls() )
    {
      Robot.makeDark();
    }      
    // 3. exit room
    Rooms.exitRoom();
  }

  public static void enterRoom()
  {
    Robot.move();
    Robot.turnLeft();
    Robot.move();
  }

  public static void exitRoom()
  {
    Lesson.turnAround();
    Robot.move();
    Robot.turnLeft();
    Robot.move();
  }
  
  public static boolean surroundedByWalls()
  {  // && means AND --> true if both conditions are true
     // || means OR  --> true if either condition is true
    return leftHasWall() && rightHasWall();
  }
  
  public static boolean leftHasWall()
  {
    Robot.turnLeft();
    
    if ( ! Robot.frontIsClear() )
    {
      Lesson.turnRight();
      return true;   // immediately exit with answer
    }
    else
    {
      Lesson.turnRight();
      return false;
    }    
  }
  
  public static boolean rightHasWall()
  {
    Lesson.turnRight();
    if ( ! Robot.frontIsClear() )
    {
      Robot.turnLeft();
      return true;
    }
    else
    {
      Robot.turnLeft();
      return false;
    }
  }
  

}  // end class