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/* TTT.java - A Tic-tac-toe Applet.
*
* <APPLET CODE="TTT" WIDTH="325" HEIGHT="385"> </APPLET>
*
* (C) 1999 by Wayne Pollock, Tampa Florida USA. All Rights Reserved.
*/
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class TTT extends Applet implements ActionListener {
private Panel controls = new Panel();
private Panel scores = new Panel();
private Panel board = new Panel();
private Button[] squares = new Button[9+1];
private Button newGame = new Button( "New Game" );
private Button clearScores = new Button( "Clear Scores" );
private TextField myScore = new TextField( "0" );
private TextField yourScore = new TextField( "0" );
private Label title = new Label( " Tic-Tac-Toe" );
private Label caption = new Label();
private Label IWon = new Label( " I Won" );
private Label youWon = new Label( "You Won" );
private boolean IAmX = false; // X goes first!
private Font XOFont = new Font("SansSerif", Font.BOLD, 64);
private int[][] possibleWins = {
{ 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 }, // rows 1, 2, and 3
{ 1, 4, 7 }, { 2, 5, 8 }, { 3, 6, 9 }, // cols 1, 2, and 3
{ 1, 5, 9 }, { 3, 5, 7 } // diagonals 1 and 2
};
public void init () {
setBackground( Color.gray );
setLayout( new BorderLayout(5, 5) );
board.setLayout( new GridLayout(3, 3, 4, 4) );
board.setBackground( Color.black );
for (int i=1; i<=9; ++i) {
squares[i] = new Button( " " );
squares[i].setBackground( Color.white );
squares[i].setFont( XOFont );
squares[i].setActionCommand( "" + i );
squares[i].addActionListener(this);
board.add( squares[i] );
}
add( board, "Center" );
yourScore.setBackground ( Color.white );
yourScore.setEnabled( false );
myScore.setBackground ( Color.white );
myScore.setEnabled( false );
title.setFont( new Font("Serif", Font.BOLD, 18) );
title.setForeground( Color.yellow );
IWon.setForeground( Color.black );
youWon.setForeground( Color.black );
scores.setLayout( new FlowLayout() );
scores.add( youWon );
scores.add( yourScore );
scores.add( title );
scores.add( myScore );
scores.add( IWon );
add( scores, "North" );
Panel p = new Panel();
p.setLayout( new BorderLayout(1,1) );
newGame.addActionListener(this);
newGame.setForeground( Color.green.darker().darker() );
clearScores.addActionListener(this);
clearScores.setForeground( Color.red.darker() );
controls.setLayout( new FlowLayout() );
controls.add( newGame );
controls.add( new Label(" ") ); // Just a spacer
controls.add( clearScores );
p.add( controls, "North" );
caption.setForeground( Color.yellow );
caption.setText( "\u00A9 1999 by Wayne Pollock, " +
"Tampa Florida USA." );
Panel capP = new Panel();
capP.setLayout( new FlowLayout() );
capP.add( caption );
p.add( capP, "South" );
add( p, "South" );
}
public void actionPerformed( ActionEvent e ) {
String whichButton = e.getActionCommand();
if ( whichButton.equals( "Clear Scores" ) )
clearScores();
else if ( whichButton.equals( "New Game" ) )
newGame();
else // User clicked on the board
makeYourMove( Integer.parseInt(whichButton) );
caption.requestFocus(); // Hides the ugly focus indicator
}
private void clearScores () {
myScore.setText( "0" );
yourScore.setText( "0" );
newGame();
}
private void newGame () {
IWon.setForeground( Color.black );
youWon.setForeground( Color.black );
for (int i=1; i<=9; ++i) {
squares[i].setLabel( " " );
squares[i].setEnabled( true );
}
IAmX = ! IAmX; // Take turns going first.
if ( IAmX )
makeMyMove();
}
private void makeYourMove ( int where ) {
if ( IAmX )
squares[where].setLabel( "O" );
else
squares[where].setLabel( "X" );
squares[where].setEnabled( false );
makeMyMove();
}
private void makeMyMove () {
int move = -1, possibilities[] = new int[8];
update( possibilities );
// First check for win (3 in a row):
for (int i=0; i<possibilities.length; ++i) {
if ( possibilities[i] == 3 || possibilities[i] == -3) {
gameOver( "Player" ); // A win for the player
return;
}
}
// With a total of 2 or -2, either the computer can win
// on this move, or else the computer must block the Player.
for (int i=0; i<possibilities.length; ++i) {
switch ( possibilities[i] ) {
case 2:
move = findEmpty( possibleWins[i] );
if ( IAmX ) {
squares[move].setLabel( "X" );
gameOver( "Computer" );
return;
}
break;
case -2:
move = findEmpty( possibleWins[i] );
if ( ! IAmX ) {
squares[move].setLabel( "O" );
gameOver( "Computer" );
return;
}
break;
}
}
// If we can't win, check if a blocking move was found:
if ( move >= 0 ) {
if ( IAmX )
squares[move].setLabel( "X" );
else
squares[move].setLabel( "O" );
squares[move].setEnabled( false );
return;
}
// If we get to here, no wins or blocks are possible
// so make the best available move:
int bestMoves[] =
{ 5, 1, 3, 7, 9, 2, 8, 4, 6 }; // In order from best to worst
for (int i=0; i<bestMoves.length; ++i) {
String status = squares[ bestMoves[i] ].getLabel();
if ( status.equals( " " ) ) { // Found an empty square!
if ( IAmX )
squares[ bestMoves[i] ].setLabel( "X" );
else
squares[ bestMoves[i] ].setLabel( "O" );
squares[ bestMoves[i] ].setEnabled( false );
return;
}
}
// If we get to here, the game is a draw!
IWon.setForeground( Color.black );
youWon.setForeground( Color.black );
}
// When game ends, update winner's score and disable the game grid:
private void gameOver ( String winner ) {
TextField scoreToUpdate;
if ( winner.equals( "Player" ) ) {
scoreToUpdate = yourScore;
youWon.setForeground( Color.cyan );
IWon.setForeground( Color.black );
} else {
scoreToUpdate = myScore;
youWon.setForeground( Color.black );
IWon.setForeground( Color.cyan );
}
int score = Integer.parseInt( scoreToUpdate.getText() ) + 1;
scoreToUpdate.setText( "" + score );
for (int i=1; i<=9; ++i)
squares[i].setEnabled( false );
}
// Locate the empty square in a row (or column or diagonal).
// (This method is never called unless exactly one square is empty.)
private int findEmpty ( int[] aRow ) {
int i;
for (i=0; i<aRow.length; ++i)
if ( squares[ aRow[i] ].getLabel().equals( " " ) )
break;
return aRow[i];
}
// There are eight possible ways to score three in a row. This
// method calculates a score for each possibility by adding one
// for each X and adding -1 for each O. So a score of 3 (or -3)
// would show X (or O) has three in a row. A score of 2 (or -2)
// would show two in a row (and one empty square) for X (or O).
// Scores of zero or 1 (or -1) have different possibile meanings,
// but this program only needs to check for a 3 (-3) or a 2 (-2).
private void update ( int[] possibilities ) {
int val=0;
for (int i=0; i<possibilities.length; ++i)
possibilities[i] = 0;
for (int squareNum=1; squareNum<=9; ++squareNum) {
switch ( squares[squareNum].getLabel().charAt(0) ) {
case 'X': val = 1; break;
case 'O': val = -1; break;
case ' ': val = 0; break;
}
for (int which=0; which<possibleWins.length; ++which) {
if ( isPartOf( squareNum, possibleWins[which] ) )
possibilities[which] += val;
}
}
}
private boolean isPartOf (int num, int[] aRow ) {
for (int i=0; i<aRow.length; ++i)
if ( num == aRow[i] )
return true;
return false;
}
}
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