naffis.com

Tic-Tac-Toe PHP Script

Posted 06/12/2006 by dnaffis 0 CommentsAdd Your Comment

Here’s a PHP script that plays Tic-Tac-Toe. It’s pretty dumb, makes completely random moves.

This was the starting point for a tic-tac-toe game that used a Bayes classifier classifier (Bayesian? see Baye’s Theorem) to decide its next move.

You can play it here http://www.naffis.com/randomstuff/ttt.php ttt.php

<?php

    $boxes = array("", "", "", "", "", "", "", "", "");

    if($HTTP_POST_VARS) {
        for($i = 0; $i < count($boxes); $i++) {
            $boxes[$i]= $HTTP_POST_VARS['move'.$i];
        }
    }

    $winner = checkForWin($boxes);
    $done = checkDone($boxes);

    if($winner == '' && !$done) {
        if(!isFirstMove($boxes)) {
            $move = makeMove($boxes);
            $boxes[$move] = 'o';
            $winner = checkForWin($boxes);
        }
    }

?>

<script language="JavaScript">
        function makeMove(cell) {
            var formCell = eval("document.ttt."+cell);

            if(document.ttt.play.value != '') {
                alert('The game is over');
                return;
            }

            if(formCell.value == 'x') {
                alert('You already moved there');
                return;
            }

            if(formCell.value == 'o') {
                alert('You cannot move there');
                return;
            }

            formCell.value = 'x';
            document.ttt.submit();
        }
    </script>

<style type="text/css">
        .main{
            border:#9999CC solid 2px;
            width:500px
        }

        .but{
            font-family:comic sans ms,verdana,arial,helvetica;
            font-size:30pt;
            font-weight:bold;
            background:#3300FF;
            width:100px;
            height:100px;
            border:#000000 solid 1px;
            cursor:hand;
            color:#EFEFFF
        }

        .but_o{
            font-family:comic sans ms,verdana,arial,helvetica;
            font-size:30pt;
            font-weight:bold;
            background:#EFEFFF;
            width:100px;
            height:100px;
            border:#CC0000 solid 1px;
            cursor:hand;
            color:#9999CC
        }

        .but_d{
            font-family:comic sans ms,verdana,arial,helvetica;
            font-size:30pt;
            font-weight:bold;
            background:#EFEFFF;
            width:100px;
            height:100px;
            border:#CC0000 solid 1px;
            cursor:hand;
            color:#EFEFFF
        }
    </style>

<?php
    echo "<form name=ttt method=post action=ttt.php>";
    echo "<input type=hidden name=play value=".$winner.">";
    echo "<table cellspacing=0 cellpadding=0 border=0 align=center width=300 height=300>";

    for($i = 0; $i < count($boxes); $i++) {
        if(($i+1) % 3 == 1)
            echo '<tr>';
        echo '<td valign=middle align=center>';
        echo "<input value='".$boxes[$i]."' type=button name=move class=but onclick=makeMove('move".$i.$j."') onMouseover=\"this.className='but_o'\" onMouseout=\"this.className='but'\" onMousedown=\"this.className='but_d'\">";
        echo '<input type=hidden name=\'move'.$i.'\' value=\''.$boxes[$i].'\'>';
        echo '</td>';
        if(($i+1) % 3 == 0)
            echo '</tr>';
    }

    echo "</table>";
    echo "</form>";
    echo "<br>";
    echo "<center><font size=6 color=blue>";
    if($winner == 'x') {
        echo 'X Wins';
        echo "<br>";
        echo "<a href=http://www.naffis.com/randomstuff/ttt.php>Play Again</a>";
    }
    else if($winner == 'o') {
        echo 'O Wins';
        echo "<br>";
        echo "<a href=http://www.naffis.com/randomstuff/ttt.php>Play Again</a>";
    }
    else if($winner == '' && $done) {
        echo 'Tie Game';
        echo "<br>";
        echo "<a href=http://www.naffis.com/randomstuff/ttt.php>Play Again</a>";
    }
    echo "</font></center>";
?>

Handle the moves:

<?php
    // check if someone won
    function checkForWin($boxarray) {
        // 0 1 2 = 3
        // 3 4 5 = 12
        // 6 7 8 = 21
        // 0 3 6 = 9
        // 1 4 7 = 12
        // 2 5 8 = 15
        // 0 4 8 = 12
        // 2 4 6 = 12

        $winner = '';

        if($boxarray[0] == $boxarray[1] && $boxarray[1] == $boxarray[2])
            $winner = $boxarray[0];
        else if($boxarray[3] == $boxarray[4] && $boxarray[4] == $boxarray[5])
            $winner = $boxarray[3];
        else if($boxarray[6] == $boxarray[7] && $boxarray[7] == $boxarray[8])
            $winner = $boxarray[6];
        else if($boxarray[0] == $boxarray[3] && $boxarray[3] == $boxarray[6])
            $winner = $boxarray[0];
        else if($boxarray[1] == $boxarray[4] && $boxarray[4] == $boxarray[7])
            $winner = $boxarray[1];
        else if($boxarray[2] == $boxarray[5] && $boxarray[5] == $boxarray[8])
            $winner = $boxarray[2];
        else if($boxarray[0] == $boxarray[4] && $boxarray[4] == $boxarray[8])
            $winner = $boxarray[0];
        else if($boxarray[2] == $boxarray[4] && $boxarray[4] == $boxarray[6])
            $winner = $boxarray[2];

        return $winner;
    }

    function isFirstMove($boxarray) {
        // check if this is the first move
        $firstmove = true;
        for($i = 0; $i < count($boxarray); $i++) {
            if($boxarray[$i] != '')
                $firstmove = false;
        }
        return $firstmove;
    }

    function makeMove($boxarray) {
        // computer makes a move
        // pick a random box to move to (0 to 8)
        srand((double)microtime()*1000000);
        $slot = rand(0,8);
        while($boxarray[$slot] == 'x' || $boxarray[$slot] == 'o')
            $slot = rand(0,8);
        return $slot;
    }

    function checkDone($boxarray) {
        $done = true;
        for($i = 0; $i < count($boxarray); $i++) {
            if($boxarray[$i] == '')
                $done = false;
        }
        return $done;
    }

?>