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qt3/doc/html/tictac-example.html

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<title>Tic Tac Toe</title>
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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Tic Tac Toe</h1>
<p>
This is an implementation of the Tic-tac-toe game.
<p> We didn't put much effort in making a clever algorithm so it's not a
challenge to play against the computer. Instead, study the source code
to see how you can make reusable components such as the <em>TicTacGameBoard</em>
widget.
<p> <hr>
<p> Header file:
<p> <pre>/****************************************************************************
** $Id: qt/tictac.h 3.3.8 edited Jan 11 14:37 $
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of an example program for Qt. This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/
#ifndef TICTAC_H
#define TICTAC_H
#include &lt;<a href="qpushbutton-h.html">qpushbutton.h</a>&gt;
#include &lt;<a href="qptrvector-h.html">qptrvector.h</a>&gt;
class QComboBox;
class QLabel;
// --------------------------------------------------------------------------
// TicTacButton implements a single tic-tac-toe button
//
class TicTacButton : public <a href="qpushbutton.html">QPushButton</a>
{
<a href="metaobjects.html#Q_OBJECT">Q_OBJECT</a>
public:
TicTacButton( <a href="qwidget.html">QWidget</a> *parent );
enum Type { Blank, Circle, Cross };
Type type() const { return t; }
void setType( Type type ) { t = type; repaint(); }
<a href="qsizepolicy.html">QSizePolicy</a> sizePolicy() const
{ return QSizePolicy( QSizePolicy::Preferred, QSizePolicy::Preferred ); }
<a href="qsize.html">QSize</a> sizeHint() const { return QSize( 32, 32 ); }
<a href="qsize.html">QSize</a> minimumSizeHint() const { return QSize( 10, 10 ); }
protected:
void drawButtonLabel( <a href="qpainter.html">QPainter</a> * );
private:
Type t;
};
// Using template vector to make vector-class of TicTacButton.
// This vector is used by the TicTacGameBoard class defined below.
typedef QPtrVector&lt;TicTacButton&gt; TicTacButtons;
typedef QMemArray&lt;int&gt; TicTacArray;
// --------------------------------------------------------------------------
// TicTacGameBoard implements the tic-tac-toe game board.
// TicTacGameBoard is a composite widget that contains N x N TicTacButtons.
// N is specified in the constructor.
//
class TicTacGameBoard : public <a href="qwidget.html">QWidget</a>
{
Q_OBJECT
public:
TicTacGameBoard( int n, QWidget *parent=0, const char *name=0 );
~TicTacGameBoard();
enum State { Init, HumansTurn, HumanWon, ComputerWon, NobodyWon };
State state() const { return st; }
void computerStarts( bool v );
void newGame();
signals:
void finished(); // game finished
private slots:
void buttonClicked();
private:
void setState( State state ) { st = state; }
void updateButtons();
int checkBoard( TicTacArray * );
void computerMove();
State st;
int nBoard;
bool comp_starts;
TicTacArray *btArray;
TicTacButtons *buttons;
};
// --------------------------------------------------------------------------
// TicTacToe implements the complete game.
// TicTacToe is a composite widget that contains a TicTacGameBoard and
// two push buttons for starting the game and quitting.
//
class TicTacToe : public <a href="qwidget.html">QWidget</a>
{
Q_OBJECT
public:
TicTacToe( int boardSize=3, QWidget *parent=0, const char *name=0 );
private slots:
void newGameClicked();
void gameOver();
private:
void newState();
<a href="qcombobox.html">QComboBox</a> *whoStarts;
<a href="qpushbutton.html">QPushButton</a> *newGame;
<a href="qpushbutton.html">QPushButton</a> *quit;
<a href="qlabel.html">QLabel</a> *message;
TicTacGameBoard *board;
};
#endif // TICTAC_H
</pre>
<p> <hr>
<p> Implementation:
<p> <pre>/****************************************************************************
** $Id: qt/tictac.cpp 3.3.8 edited Jan 11 14:37 $
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of an example program for Qt. This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/
#include "tictac.h"
#include &lt;<a href="qapplication-h.html">qapplication.h</a>&gt;
#include &lt;<a href="qpainter-h.html">qpainter.h</a>&gt;
#include &lt;<a href="qdrawutil-h.html">qdrawutil.h</a>&gt;
#include &lt;<a href="qcombobox-h.html">qcombobox.h</a>&gt;
#include &lt;<a href="qcheckbox-h.html">qcheckbox.h</a>&gt;
#include &lt;<a href="qlabel-h.html">qlabel.h</a>&gt;
#include &lt;<a href="qlayout-h.html">qlayout.h</a>&gt;
#include &lt;stdlib.h&gt; // rand() function
#include &lt;<a href="qdatetime-h.html">qdatetime.h</a>&gt; // seed for rand()
//***************************************************************************
//* TicTacButton member functions
//***************************************************************************
// --------------------------------------------------------------------------
// Creates a TicTacButton
//
<a name="f188"></a>TicTacButton::TicTacButton( <a href="qwidget.html">QWidget</a> *parent ) : <a href="qpushbutton.html">QPushButton</a>( parent )
{
t = Blank; // initial type
}
// --------------------------------------------------------------------------
// Paints TicTacButton
//
<a name="x31"></a>void TicTacButton::<a href="qbutton.html#drawButtonLabel">drawButtonLabel</a>( <a href="qpainter.html">QPainter</a> *p )
{
<a href="qrect.html">QRect</a> r = <a href="qwidget.html#rect">rect</a>();
p-&gt;<a href="qpainter.html#setPen">setPen</a>( QPen( white,2 ) ); // set fat pen
if ( t == Circle ) {
<a name="x36"></a><a name="x35"></a><a name="x28"></a> p-&gt;<a href="qpainter.html#drawEllipse">drawEllipse</a>( r.<a href="qrect.html#left">left</a>()+4, r.<a href="qrect.html#top">top</a>()+4, r.<a href="qrect.html#width">width</a>()-8, r.<a href="qrect.html#height">height</a>()-8 );
} else if ( t == Cross ) { // draw cross
<a name="x37"></a><a name="x33"></a> p-&gt;<a href="qpainter.html#drawLine">drawLine</a>( r.<a href="qrect.html#topLeft">topLeft</a>() +QPoint(4,4), r.<a href="qrect.html#bottomRight">bottomRight</a>()-QPoint(4,4));
<a name="x38"></a><a name="x32"></a> p-&gt;<a href="qpainter.html#drawLine">drawLine</a>( r.<a href="qrect.html#bottomLeft">bottomLeft</a>()+QPoint(4,-4),r.<a href="qrect.html#topRight">topRight</a>() -QPoint(4,-4));
}
}
//***************************************************************************
//* TicTacGameBoard member functions
//***************************************************************************
// --------------------------------------------------------------------------
// Creates a game board with N x N buttons and connects the "clicked()"
// signal of all buttons to the "buttonClicked()" slot.
//
<a name="f189"></a>TicTacGameBoard::TicTacGameBoard( int n, QWidget *parent, const char *name )
: <a href="qwidget.html">QWidget</a>( parent, name )
{
st = Init; // initial state
nBoard = n;
n *= n; // make square
comp_starts = FALSE; // human starts
buttons = new TicTacButtons(n); // create real buttons
btArray = new TicTacArray(n); // create button model
<a href="qgridlayout.html">QGridLayout</a> * grid = new <a href="qgridlayout.html">QGridLayout</a>( this, nBoard, nBoard, 4 );
<a href="qpalette.html">QPalette</a> p( blue );
for ( int i=0; i&lt;n; i++ ) { // create and connect buttons
TicTacButton *ttb = new TicTacButton( this );
<a name="x45"></a> ttb-&gt;<a href="qwidget.html#setPalette">setPalette</a>( p );
ttb-&gt;<a href="qwidget.html#setEnabled">setEnabled</a>( FALSE );
<a href="qobject.html#connect">connect</a>( ttb, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), SLOT(buttonClicked()) );
grid-&gt;<a href="qgridlayout.html#addWidget">addWidget</a>( ttb, i%nBoard, i/nBoard );
buttons-&gt;insert( i, ttb );
btArray-&gt;at(i) = TicTacButton::Blank; // initial button type
}
<a name="x40"></a> <a href="qtime.html">QTime</a> t = QTime::<a href="qtime.html#currentTime">currentTime</a>(); // set random seed
<a name="x43"></a><a name="x42"></a><a name="x41"></a> srand( t.<a href="qtime.html#hour">hour</a>()*12+t.<a href="qtime.html#minute">minute</a>()*60+t.<a href="qtime.html#second">second</a>()*60 );
}
TicTacGameBoard::~TicTacGameBoard()
{
delete buttons;
delete btArray;
}
// --------------------------------------------------------------------------
// TicTacGameBoard::computerStarts( bool v )
//
// Computer starts if v=TRUE. The human starts by default.
//
void <a name="f190"></a>TicTacGameBoard::computerStarts( bool v )
{
comp_starts = v;
}
// --------------------------------------------------------------------------
// TicTacGameBoard::newGame()
//
// Clears the game board and prepares for a new game
//
void <a name="f191"></a>TicTacGameBoard::newGame()
{
st = HumansTurn;
for ( int i=0; i&lt;nBoard*nBoard; i++ )
btArray-&gt;at(i) = TicTacButton::Blank;
if ( comp_starts )
computerMove();
else
updateButtons();
}
// --------------------------------------------------------------------------
// TicTacGameBoard::buttonClicked() - SLOT
//
// This slot is activated when a TicTacButton emits the signal "clicked()",
// i.e. the user has clicked on a TicTacButton.
//
void <a name="f192"></a>TicTacGameBoard::buttonClicked()
{
if ( st != HumansTurn ) // not ready
return;
int i = buttons-&gt;findRef( (TicTacButton*)<a href="qobject.html#sender">sender</a>() );
TicTacButton *b = buttons-&gt;at(i); // get piece that was pressed
if ( b-&gt;type() == TicTacButton::Blank ) { // empty piece?
btArray-&gt;at(i) = TicTacButton::Circle;
updateButtons();
if ( checkBoard( btArray ) == 0 ) // not a winning move?
computerMove();
int s = checkBoard( btArray );
if ( s ) { // any winners yet?
st = s == TicTacButton::Circle ? HumanWon : ComputerWon;
emit finished();
}
}
}
// --------------------------------------------------------------------------
// TicTacGameBoard::updateButtons()
//
// Updates all buttons that have changed state
//
void <a name="f193"></a>TicTacGameBoard::updateButtons()
{
for ( int i=0; i&lt;nBoard*nBoard; i++ ) {
if ( buttons-&gt;at(i)-&gt;type() != btArray-&gt;at(i) )
buttons-&gt;at(i)-&gt;setType( (TicTacButton::Type)btArray-&gt;at(i) );
buttons-&gt;at(i)-&gt;setEnabled( buttons-&gt;at(i)-&gt;type() ==
TicTacButton::Blank );
}
}
// --------------------------------------------------------------------------
// TicTacGameBoard::checkBoard()
//
// Checks if one of the players won the game, works for any board size.
//
// Returns:
// - TicTacButton::Cross if the player with X buttons won
// - TicTacButton::Circle if the player with O buttons won
// - Zero (0) if there is no winner yet
//
int <a name="f194"></a>TicTacGameBoard::checkBoard( TicTacArray *a )
{
int t = 0;
int row, col;
bool won = FALSE;
for ( row=0; row&lt;nBoard &amp;&amp; !won; row++ ) { // check horizontal
t = a-&gt;at(row*nBoard);
if ( t == TicTacButton::Blank )
continue;
col = 1;
while ( col&lt;nBoard &amp;&amp; a-&gt;at(row*nBoard+col) == t )
col++;
if ( col == nBoard )
won = TRUE;
}
for ( col=0; col&lt;nBoard &amp;&amp; !won; col++ ) { // check vertical
t = a-&gt;at(col);
if ( t == TicTacButton::Blank )
continue;
row = 1;
while ( row&lt;nBoard &amp;&amp; a-&gt;at(row*nBoard+col) == t )
row++;
if ( row == nBoard )
won = TRUE;
}
if ( !won ) { // check diagonal top left
t = a-&gt;at(0); // to bottom right
if ( t != TicTacButton::Blank ) {
int i = 1;
while ( i&lt;nBoard &amp;&amp; a-&gt;at(i*nBoard+i) == t )
i++;
if ( i == nBoard )
won = TRUE;
}
}
if ( !won ) { // check diagonal bottom left
int j = nBoard-1; // to top right
int i = 0;
t = a-&gt;at(i+j*nBoard);
if ( t != TicTacButton::Blank ) {
i++; j--;
while ( i&lt;nBoard &amp;&amp; a-&gt;at(i+j*nBoard) == t ) {
i++; j--;
}
if ( i == nBoard )
won = TRUE;
}
}
if ( !won ) // no winner
t = 0;
return t;
}
// --------------------------------------------------------------------------
// TicTacGameBoard::computerMove()
//
// Puts a piece on the game board. Very, very simple.
//
void <a name="f195"></a>TicTacGameBoard::computerMove()
{
int numButtons = nBoard*nBoard;
int *altv = new int[numButtons]; // buttons alternatives
int altc = 0;
int stopHuman = -1;
TicTacArray a = btArray-&gt;copy();
int i;
for ( i=0; i&lt;numButtons; i++ ) { // try all positions
if ( a[i] != TicTacButton::Blank ) // already a piece there
continue;
a[i] = TicTacButton::Cross; // test if computer wins
if ( checkBoard(&amp;a) == a[i] ) { // computer will win
st = ComputerWon;
stopHuman = -1;
break;
}
a[i] = TicTacButton::Circle; // test if human wins
if ( checkBoard(&amp;a) == a[i] ) { // oops...
stopHuman = i; // remember position
a[i] = TicTacButton::Blank; // restore button
continue; // computer still might win
}
a[i] = TicTacButton::Blank; // restore button
altv[altc++] = i; // remember alternative
}
if ( stopHuman &gt;= 0 ) // must stop human from winning
a[stopHuman] = TicTacButton::Cross;
else if ( i == numButtons ) { // tried all alternatives
if ( altc &gt; 0 ) // set random piece
a[altv[rand()%(altc--)]] = TicTacButton::Cross;
if ( altc == 0 ) { // no more blanks
st = NobodyWon;
emit finished();
}
}
*btArray = a; // update model
updateButtons(); // update buttons
delete[] altv;
}
//***************************************************************************
//* TicTacToe member functions
//***************************************************************************
// --------------------------------------------------------------------------
// Creates a game widget with a game board and two push buttons, and connects
// signals of child widgets to slots.
//
<a name="f196"></a>TicTacToe::TicTacToe( int boardSize, QWidget *parent, const char *name )
: <a href="qwidget.html">QWidget</a>( parent, name )
{
<a href="qvboxlayout.html">QVBoxLayout</a> * l = new <a href="qvboxlayout.html">QVBoxLayout</a>( this, 6 );
// Create a message label
message = new <a href="qlabel.html">QLabel</a>( this );
<a name="x24"></a> message-&gt;<a href="qframe.html#setFrameStyle">setFrameStyle</a>( QFrame::WinPanel | QFrame::Sunken );
message-&gt;<a href="qlabel.html#setAlignment">setAlignment</a>( AlignCenter );
l-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( message );
// Create the game board and connect the signal finished() to this
// gameOver() slot
board = new TicTacGameBoard( boardSize, this );
<a href="qobject.html#connect">connect</a>( board, SIGNAL(finished()), SLOT(gameOver()) );
l-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( board );
// Create a horizontal frame line
<a href="qframe.html">QFrame</a> *line = new <a href="qframe.html">QFrame</a>( this );
line-&gt;<a href="qframe.html#setFrameStyle">setFrameStyle</a>( QFrame::HLine | QFrame::Sunken );
l-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( line );
// Create the combo box for deciding who should start, and
// connect its clicked() signals to the buttonClicked() slot
whoStarts = new <a href="qcombobox.html">QComboBox</a>( this );
<a name="x23"></a> whoStarts-&gt;<a href="qcombobox.html#insertItem">insertItem</a>( "Computer starts" );
whoStarts-&gt;<a href="qcombobox.html#insertItem">insertItem</a>( "Human starts" );
l-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( whoStarts );
// Create the push buttons and connect their clicked() signals
// to this right slots.
newGame = new <a href="qpushbutton.html">QPushButton</a>( "Play!", this );
<a href="qobject.html#connect">connect</a>( newGame, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), SLOT(newGameClicked()) );
quit = new <a href="qpushbutton.html">QPushButton</a>( "Quit", this );
<a href="qobject.html#connect">connect</a>( quit, SIGNAL(<a href="qbutton.html#clicked">clicked</a>()), qApp, SLOT(<a href="qapplication.html#quit">quit</a>()) );
<a href="qhboxlayout.html">QHBoxLayout</a> * b = new <a href="qhboxlayout.html">QHBoxLayout</a>;
<a name="x19"></a> l-&gt;<a href="qboxlayout.html#addLayout">addLayout</a>( b );
b-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( newGame );
b-&gt;<a href="qboxlayout.html#addWidget">addWidget</a>( quit );
newState();
}
// --------------------------------------------------------------------------
// TicTacToe::newGameClicked() - SLOT
//
// This slot is activated when the new game button is clicked.
//
void <a name="f197"></a>TicTacToe::newGameClicked()
{
<a name="x22"></a> board-&gt;computerStarts( whoStarts-&gt;<a href="qcombobox.html#currentItem">currentItem</a>() == 0 );
board-&gt;newGame();
newState();
}
// --------------------------------------------------------------------------
// TicTacToe::gameOver() - SLOT
//
// This slot is activated when the TicTacGameBoard emits the signal
// "finished()", i.e. when a player has won or when it is a draw.
//
void <a name="f198"></a>TicTacToe::gameOver()
{
newState(); // update text box
}
// --------------------------------------------------------------------------
// Updates the message to reflect a new state.
//
void <a name="f199"></a>TicTacToe::newState()
{
static const char *msg[] = { // TicTacGameBoard::State texts
"Click Play to start", "Make your move",
"You won!", "Computer won!", "It's a draw" };
message-&gt;<a href="qlabel.html#setText">setText</a>( msg[board-&gt;state()] );
return;
}
</pre>
<p> <hr>
<p> Main:
<p> <pre>/****************************************************************************
** $Id: qt/main.cpp 3.3.8 edited Jan 11 14:37 $
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of an example program for Qt. This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/
#include &lt;<a href="qapplication-h.html">qapplication.h</a>&gt;
#include &lt;stdlib.h&gt;
#include "tictac.h"
int main( int argc, char **argv )
{
<a href="qapplication.html">QApplication</a> a( argc, argv );
int n = 3;
if ( argc == 2 ) // get board size n
n = atoi(argv[1]);
if ( n &lt; 3 || n &gt; 10 ) { // out of range
<a href="qapplication.html#qWarning">qWarning</a>( "%s: Board size must be from 3x3 to 10x10", argv[0] );
return 1;
}
TicTacToe ttt( n ); // create game
a.<a href="qapplication.html#setMainWidget">setMainWidget</a>( &amp;ttt );
ttt.<a href="qwidget.html#setCaption">setCaption</a>("Qt Example - TicTac");
ttt.<a href="qwidget.html#show">show</a>(); // show widget
return a.<a href="qapplication.html#exec">exec</a>(); // go
}
</pre>
<p>See also <a href="examples.html">Examples</a>.
<!-- eof -->
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<table width=100% cellspacing=0 border=0><tr>
<td>Copyright &copy; 2007
<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
<td align=right><div align=right>Qt 3.3.8</div>
</table></div></address></body>
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