// file:    Pair.java
// author:  Robert Keller
// purpose: Represent a pair of row, column coordinates on a grid.

/**
 * A Pair maintains a pair of int's, row and col.  These are publicly 
 * accessible.
 */

class Pair
  {
  public int row;
  public int col;

  /**
   * Create a Pair from row and Column.
   */

  Pair(int row, int col)
    {
    this.row = row;
    this.col = col;
    }


  /**
   * Indicate whether this Pair is adjacent on the Grid to the argument Pair.
   */

  public boolean adjacent(Pair other)
    {
    return (row == other.row && (col == other.col-1 || col == other.col+1))
        || (col == other.col && (row == other.row-1 || row == other.row+1));
    }


  /**
   * Equality test for Pairs.
   */

  public boolean equals(Pair other)
    {
    return row == other.row
        && col == other.col;
    }


  /**
   * Provide a String representation of this Pair.
   */

  public String toString()
    {
    return row + " " + col;
    }
  }