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This is an implementation of the Tic-tac-toe game.
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 TicTacGameBoard widget.
Header file:
/****************************************************************************
** $Id: qt/tictac.h 3.0.5 edited Oct 12 2001 $
**
** Copyright (C) 1992-2000 Trolltech AS. 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 <qpushbutton.h>
#include <qptrvector.h>
class QComboBox;
class QLabel;
// --------------------------------------------------------------------------
// TicTacButton implements a single tic-tac-toe button
//
class TicTacButton : public QPushButton
{
Q_OBJECT
public:
TicTacButton( QWidget *parent );
enum Type { Blank, Circle, Cross };
Type type() const { return t; }
void setType( Type type ) { t = type; repaint(); }
QSizePolicy sizePolicy() const
{ return QSizePolicy( QSizePolicy::Preferred, QSizePolicy::Preferred ); }
QSize sizeHint() const { return QSize( 32, 32 ); }
QSize minimumSizeHint() const { return QSize( 10, 10 ); }
protected:
void drawButtonLabel( QPainter * );
private:
Type t;
};
// Using template vector to make vector-class of TicTacButton.
// This vector is used by the TicTacGameBoard class defined below.
typedef QPtrVector<TicTacButton> TicTacButtons;
typedef QMemArray<int> 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 QWidget
{
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 QWidget
{
Q_OBJECT
public:
TicTacToe( int boardSize=3, QWidget *parent=0, const char *name=0 );
private slots:
void newGameClicked();
void gameOver();
private:
void newState();
QComboBox *whoStarts;
QPushButton *newGame;
QPushButton *quit;
QLabel *message;
TicTacGameBoard *board;
};
#endif // TICTAC_H
Implementation:
/****************************************************************************
** $Id: qt/tictac.cpp 3.0.5 edited Nov 14 2001 $
**
** Copyright (C) 1992-2000 Trolltech AS. 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 <qapplication.h>
#include <qpainter.h>
#include <qdrawutil.h>
#include <qcombobox.h>
#include <qcheckbox.h>
#include <qlabel.h>
#include <qlayout.h>
#include <stdlib.h> // rand() function
#include <qdatetime.h> // seed for rand()
//***************************************************************************
//* TicTacButton member functions
//***************************************************************************
// --------------------------------------------------------------------------
// Creates a TicTacButton
//
TicTacButton::TicTacButton( QWidget *parent ) : QPushButton( parent )
{
t = Blank; // initial type
}
// --------------------------------------------------------------------------
// Paints TicTacButton
//
void TicTacButton::drawButtonLabel( QPainter *p )
{
QRect r = rect();
p->setPen( QPen( white,2 ) ); // set fat pen
if ( t == Circle ) {
p->drawEllipse( r.left()+4, r.top()+4, r.width()-8, r.height()-8 );
} else if ( t == Cross ) { // draw cross
p->drawLine( r.topLeft() +QPoint(4,4), r.bottomRight()-QPoint(4,4));
p->drawLine( r.bottomLeft()+QPoint(4,-4),r.topRight() -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.
//
TicTacGameBoard::TicTacGameBoard( int n, QWidget *parent, const char *name )
: QWidget( 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
QGridLayout * grid = new QGridLayout( this, nBoard, nBoard, 4 );
QPalette p( blue );
for ( int i=0; i<n; i++ ) { // create and connect buttons
TicTacButton *ttb = new TicTacButton( this );
ttb->setPalette( p );
ttb->setEnabled( FALSE );
connect( ttb, SIGNAL(clicked()), SLOT(buttonClicked()) );
grid->addWidget( ttb, i%nBoard, i/nBoard );
buttons->insert( i, ttb );
btArray->at(i) = TicTacButton::Blank; // initial button type
}
QTime t = QTime::currentTime(); // set random seed
srand( t.hour()*12+t.minute()*60+t.second()*60 );
}
TicTacGameBoard::~TicTacGameBoard()
{
delete buttons;
delete btArray;
}
// --------------------------------------------------------------------------
// TicTacGameBoard::computerStarts( bool v )
//
// Computer starts if v=TRUE. The human starts by default.
//
void TicTacGameBoard::computerStarts( bool v )
{
comp_starts = v;
}
// --------------------------------------------------------------------------
// TicTacGameBoard::newGame()
//
// Clears the game board and prepares for a new game
//
void TicTacGameBoard::newGame()
{
st = HumansTurn;
for ( int i=0; i<nBoard*nBoard; i++ )
btArray->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 TicTacGameBoard::buttonClicked()
{
if ( st != HumansTurn ) // not ready
return;
int i = buttons->findRef( (TicTacButton*)sender() );
TicTacButton *b = buttons->at(i); // get piece that was pressed
if ( b->type() == TicTacButton::Blank ) { // empty piece?
btArray->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 TicTacGameBoard::updateButtons()
{
for ( int i=0; i<nBoard*nBoard; i++ ) {
if ( buttons->at(i)->type() != btArray->at(i) )
buttons->at(i)->setType( (TicTacButton::Type)btArray->at(i) );
buttons->at(i)->setEnabled( buttons->at(i)->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 TicTacGameBoard::checkBoard( TicTacArray *a )
{
int t = 0;
int row, col;
bool won = FALSE;
for ( row=0; row<nBoard && !won; row++ ) { // check horizontal
t = a->at(row*nBoard);
if ( t == TicTacButton::Blank )
continue;
col = 1;
while ( col<nBoard && a->at(row*nBoard+col) == t )
col++;
if ( col == nBoard )
won = TRUE;
}
for ( col=0; col<nBoard && !won; col++ ) { // check vertical
t = a->at(col);
if ( t == TicTacButton::Blank )
continue;
row = 1;
while ( row<nBoard && a->at(row*nBoard+col) == t )
row++;
if ( row == nBoard )
won = TRUE;
}
if ( !won ) { // check diagonal top left
t = a->at(0); // to bottom right
if ( t != TicTacButton::Blank ) {
int i = 1;
while ( i<nBoard && a->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->at(i+j*nBoard);
if ( t != TicTacButton::Blank ) {
i++; j--;
while ( i<nBoard && a->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 TicTacGameBoard::computerMove()
{
int numButtons = nBoard*nBoard;
int *altv = new int[numButtons]; // buttons alternatives
int altc = 0;
int stopHuman = -1;
TicTacArray a = btArray->copy();
int i;
for ( i=0; i<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(&a) == a[i] ) { // computer will win
st = ComputerWon;
stopHuman = -1;
break;
}
a[i] = TicTacButton::Circle; // test if human wins
if ( checkBoard(&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 >= 0 ) // must stop human from winning
a[stopHuman] = TicTacButton::Cross;
else if ( i == numButtons ) { // tried all alternatives
if ( altc > 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.
//
TicTacToe::TicTacToe( int boardSize, QWidget *parent, const char *name )
: QWidget( parent, name )
{
QVBoxLayout * l = new QVBoxLayout( this, 6 );
// Create a message label
message = new QLabel( this );
message->setFrameStyle( QFrame::WinPanel | QFrame::Sunken );
message->setAlignment( AlignCenter );
l->addWidget( message );
// Create the game board and connect the signal finished() to this
// gameOver() slot
board = new TicTacGameBoard( boardSize, this );
connect( board, SIGNAL(finished()), SLOT(gameOver()) );
l->addWidget( board );
// Create a horizontal frame line
QFrame *line = new QFrame( this );
line->setFrameStyle( QFrame::HLine | QFrame::Sunken );
l->addWidget( line );
// Create the combo box for deciding who should start, and
// connect its clicked() signals to the buttonClicked() slot
whoStarts = new QComboBox( this );
whoStarts->insertItem( "Computer starts" );
whoStarts->insertItem( "Human starts" );
l->addWidget( whoStarts );
// Create the push buttons and connect their clicked() signals
// to this right slots.
newGame = new QPushButton( "Play!", this );
connect( newGame, SIGNAL(clicked()), SLOT(newGameClicked()) );
quit = new QPushButton( "Quit", this );
connect( quit, SIGNAL(clicked()), qApp, SLOT(quit()) );
QHBoxLayout * b = new QHBoxLayout;
l->addLayout( b );
b->addWidget( newGame );
b->addWidget( quit );
newState();
}
// --------------------------------------------------------------------------
// TicTacToe::newGameClicked() - SLOT
//
// This slot is activated when the new game button is clicked.
//
void TicTacToe::newGameClicked()
{
board->computerStarts( whoStarts->currentItem() == 0 );
board->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 TicTacToe::gameOver()
{
newState(); // update text box
}
// --------------------------------------------------------------------------
// Updates the message to reflect a new state.
//
void 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->setText( msg[board->state()] );
return;
}
Main:
/****************************************************************************
** $Id: qt/main.cpp 3.0.5 edited Oct 12 2001 $
**
** Copyright (C) 1992-2000 Trolltech AS. 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 <qapplication.h>
#include <stdlib.h>
#include "tictac.h"
int main( int argc, char **argv )
{
QApplication a( argc, argv );
int n = 3;
if ( argc == 2 ) // get board size n
n = atoi(argv[1]);
if ( n < 3 || n > 10 ) { // out of range
qWarning( "%s: Board size must be from 3x3 to 10x10", argv[0] );
return 1;
}
TicTacToe ttt( n ); // create game
a.setMainWidget( &ttt );
ttt.setCaption("Qt Example - TicTac");
ttt.show(); // show widget
return a.exec(); // go
}
See also Examples.
| Copyright © 2002 Trolltech | Trademarks | Qt version 3.0.5
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