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Tic Tac Toe
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.
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