/* Point.java */

/**
 *  Point :  A Point object stores a 2-D grid coordinate.
 *  Points are immutable (they can not be modified once created).
 */
public class Point { 
  /** Create a new Point initialized to (r, c)
   */
  public Point(int r, int c) {
    myRow = r;
    myCol = c;
  }

  /** Returns the row of this Point
   */
  public int row() {
    return myRow;
  }

  /** Returns the column of this Point
   */
  public int column() {
    return myCol;
  }

  /** Returns true <==> this Point's coordinates exactly match pt's
   */
  public boolean equals( Object pt ) {
    Point p = (Point) pt;
    return (myRow == p.myRow) && (myCol == p.myCol);
  }

  /** Assumes: dir == one of {NORTH, SOUTH, EAST, WEST}
   *  Returns a new Point object that is "this"  Point's position 
   *   shifted by one in the direction dir.  
   */
  Point move( int dir ) {
    Point newPoint = new Point( myRow, myCol );

    switch (dir) {
      case Direction.NORTH:
        newPoint.myRow--; break;
      case Direction.EAST:
	newPoint.myCol++; break;
      case Direction.SOUTH:
	newPoint.myRow++; break;
      case Direction.WEST:
	newPoint.myCol--; break;
    }
    return newPoint;
  }

  /** Returns a String representation of this Point
   */
  public String toString() {
    return "(" + myCol + ", " + myRow + ")";
  }

  // Data fields
  private int myRow;
  private int myCol;
};