PHP在线考试系统组卷问题

PHP实现一个在线考试系统，如果实现自动组卷，试卷内题目不重复，选择题ABCD顺序随机打乱，题目顺序打乱？

    // 此函数来自 http://php.p2hp.com/manual/zh/function.shuffle.php
    // 作者 Antonio Ognio
    function shuffle_with_keys(&$array) {
        /* Auxiliary array to hold the new order */
        $aux = array();
        /* We work with an array of the keys */
        $keys = array_keys($array);
        /* We shuffle the keys */
        shuffle($keys);
        /* We iterate thru' the new order of the keys */
        foreach($keys as $key) {
            /* We insert the key, value pair in its new order */
            $aux[$key] = $array[$key];
            /* We remove the element from the old array to save memory */
            unset($array[$key]);
        }
        /* The auxiliary array with the new order overwrites the old variable */
        $array = $aux;
    }    

    $optionText = array('A', 'B', 'C', 'D'); // 四个选项的名字

    // 注意问题的索引 1 2 3 4 ... 要和答案的索引对应
    
    $questions = array(
        1 => 'php的官方网址是？'
        ,2 => 'php是哪一年发明的？'
        ,3 => 'php之父是谁？'
        ,4 => 'php目前最新的版本是？'
    );
    
    $answers = array(
        1 => array(
            'php.org'
            ,'php.com'
            ,'php.net',
            'php.cn'
        )
        ,2 => array(
            '1990'
            ,'2000'
            ,'1999'
            ,'1994'
        )
        ,3 => array(
            'Rasmus Lerdorf'
            ,'Bill Gates'
            ,'Steve Jobs'
            ,'Larry Page'
        )
        ,4 => array(
            '5.0'
            ,'6.0'
            ,'7.0'
            ,'8.0'
        )
    );
    
    shuffle_with_keys($questions);
    
    $i = 1;
    foreach($questions as $k => $q) {
        shuffle($answers[$k]);
        echo "<p>$i.&nbsp;$q</p>";
        foreach($answers[$k] as $key => $answer) {
            echo "<p>($optionText[$key])&nbsp;$answer</p>";
        }
        $i++;
    }