/// <summary>
/// Makes a move on this Tic-Tac-Toe board at the specified move position
/// </summary>
/// <param name="move">The move to make</param>
/// <returns>A reference to this Tic-Tac-Toe board</returns>
public override Board MakeMove(Move move)
{
TTTMove m = (TTTMove)move;
//Make the move if possible, if a move has already been made at this position then throw an invalid move exception
if (boardContents[m.X, m.Y] == 0)
{
//Make the move on this board
boardContents[m.X, m.Y] = CurrentPlayer;
//Remove the move just performed from the list of possible moves
possibleMoves.Remove(m);
//Determine if there is a winner
DetermineWinner(move);
//Swap out the current player
CurrentPlayer = NextPlayer;
//Call the MakeMove method on the Board base class, to save the last move made on this board
return(base.MakeMove(move));
}
else
{
throw new InvalidMoveException("Move has already been made at: " + m.ToString());
}
}
/// <summary>
/// Determine if the current game is over <para/>
/// Uses knowledge of the last move to save computation time
/// </summary>
/// <param name="move">The last move made</param>
protected override void DetermineWinner(Move move)
{
TTTMove m = (TTTMove)move;
//Check the row and column of the last move
if (boardContents[0, m.Y] == boardContents[1, m.Y] && boardContents[1, m.Y] == boardContents[2, m.Y] || boardContents[m.X, 0] == boardContents[m.X, 1] && boardContents[m.X, 1] == boardContents[m.X, 2])
{
winner = CurrentPlayer;
return;
}
//Then check each diagonal
if (boardContents[0, 0] != 0 && boardContents[0, 0] == boardContents[1, 1] && boardContents[0, 0] == boardContents[2, 2] || boardContents[0, 2] != 0 && boardContents[0, 2] == boardContents[1, 1] && boardContents[0, 2] == boardContents[2, 0])
{
winner = CurrentPlayer;
return;
}
//If there is still no winner and the board is full, the game is a tie, otherwise no winner yet
if (PossibleMoves().Count == 0)
{
winner = 0;
}
}