public void Play()
{
// set starting player to the player who is Os
// this.currentPlayer = (this.players[0].Token == Piece.PieceValue.O) ? (byte)0 : (byte)1;
foreach (Player p in this.players)
{
this.currentPlayer = p;
if (p.Token == Piece.PieceValue.O)
{
break;
}
}
// draw the empty board
this.DrawBoard();
Console.WriteLine();
// player this game until there is a winner
while (!this.Over)
{
// get a reference to the current player
this.currentPlayer = (Player)players.Current;
// player selects a move
ushort move = this.currentPlayer.Move(this.theBoard);
// mark move on the board
this.theBoard.Place(new Piece(this.currentPlayer.Token), move);
// draw the board on the screen
Console.WriteLine("Round {0}: {1} chooses square {2}.", this.theBoard.Moves, this.currentPlayer.Token.ToString(), move);
this.DrawBoard();
Console.WriteLine();
// check to see if the most recent player won
if (this.Over = theBoard.Win(this.currentPlayer.Token))
{
this.currentPlayer.AddPoints(1);
this.PrintWinner();
}
// check to see if the game is a draw
else if (this.Over = theBoard.Full())
{
this.PrintDraw();
}
// otherwise, move to next player
else
{
players.MoveNext();
}
}
}
protected static MoveStrategy LookAhead(Piece inPiece, TicTacToeBoard inBoard, ref ushort bestMove)
{
// unused dummy value to seend the algorithm
ushort aDummy = 0;
// temporary strategy
MoveStrategy aResponse;
// the strategy to return
MoveStrategy outValue = (inPiece.Value == Piece.PieceValue.X) ? MoveStrategy.OWin - 1 : MoveStrategy.XWin + 1;
// first check to see if the game is a draw
if (inBoard.Full())
{
outValue = MoveStrategy.Draw;
}
// return any move that results in an immediate win
else if (Computer.ImmediateWin(inPiece, inBoard, ref bestMove))
{
outValue = (inPiece.Value == Piece.PieceValue.X) ? MoveStrategy.XWin : MoveStrategy.OWin;
}
// return any move that will result in blocking the other player from an immediate win on his next turn
else if (Computer.ImmediateBlock(inPiece, inBoard, ref bestMove))
{
outValue = (inPiece.Value == Piece.PieceValue.X) ? MoveStrategy.XBlock : MoveStrategy.OBlock;
}
// no immediate wins so look for a promising move
else
{
for (ushort i = 0; i < inBoard.Length; ++i)
{
if (!inBoard.At(i))
{
inBoard.Place(inPiece, i);
// swap pieces and go down a move
Piece aPiece = (inPiece.Value == Piece.PieceValue.X) ? new Piece(Piece.PieceValue.O) : new Piece(Piece.PieceValue.X);
// call look ahead recursively with a copy of the board each time
aResponse = LookAhead(aPiece, new TicTacToeBoard(inBoard), ref aDummy);
// determine the best move
switch (inPiece.Value)
{
case Piece.PieceValue.X:
if (aResponse > outValue)
{
outValue = aResponse;
bestMove = i;
}
break;
case Piece.PieceValue.O:
if (aResponse < outValue)
{
outValue = aResponse;
bestMove = i;
}
break;
default:
break;
} // end switch
} // end if
} // end for loop
} // end else
// return the best move strategy
return(outValue);
}