Simple Regular Expressions using preg_match()

Enter a string to be evaluated.

Text:

String

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CODE FOLLOWS

<?php
    include('includes/header.php');

    error_reporting(E_ALL);    // set error reporting to all

    $self = basename($_SERVER['SCRIPT_NAME']);
    $step = isset($_POST['step']) ? $_POST['step'] : 1;
    $string = isset($_POST['string']) ? $_POST['string'] : null;

    if ($step == 1) // first time into this script
        {
        ?>

            <h1>
                Simple Regular Expressions using preg_match()
            </h1>

            <p>
                Enter a string to be evaluated.
            </p>

            <form action="<?php echo($self); ?>" method="POST">

                <fieldset>
                    <legend>Text:</legend>
                    <label for="string">String</label>
                    <input type="text" size="30" id="string" name="string" value="<?php echo($string); ?>">
                </fieldset>

                <input type="hidden" name="step" value="2">
                <input type="submit" name="submit" value="Submit">
            </form>

            <?php
        }  // end of step 1


    if ($step == 2) // second time into this script
        {
        // show results and provide a form to try again

        // define arrays for search

        $a = array();
        $b = array();
        $c = array();
        $d = array();
        $e = array();
        $f = array();


        // Note the preg_match pattern used to evaluate the string provided.

        $aa = preg_match("/[A-z]/", $string, $a);
        $bb = preg_match("/[A-Z]/", $string, $b);
        $cc = preg_match("/[a-z]/", $string, $c);
        $dd = preg_match("/[A-a]/", $string, $d);
        $ee = preg_match("/tedd/", $string, $e);
        $ff = preg_match("/world/", $string, $f);

        ?>

            <h3> String Provided: <?php echo($string); ?></h3>

            <p>
                1. preg_match("/[A-z]/", <?php echo($string); ?>); = <?php if ($aa) {
                print_r($a[0]);
                } ?><br>
                2. preg_match("/[A-Z]/", <?php echo($string); ?>); = <?php if ($bb) {
                print_r($b[0]);
                } ?><br>
                3. preg_match("/[a-z]/", <?php echo($string); ?>); = <?php if ($cc) {
                print_r($c[0]);
                } ?><br>
                4. preg_match("/[A-a]/", <?php echo($string); ?>); =<?php if ($dd) {
                print_r($d[0]);
                } ?><br>
                5. preg_match("/tedd/", <?php echo($string); ?>); = <?php if ($ee) {
                print_r($e[0]);
                } ?><br>
                6. preg_match("/world/", <?php echo($string); ?>); = <?php if ($ff) {
                print_r($f[0]);
                } ?><br>
            </p>

            <p>
                Remember, these are the results of different preg_match() operations. <br>
                Try different strings to see how different expressions work.
            </p>

            <p>
                <a href="http://php.net/manual/en/function.preg-match.php">See the PHP manual</a>
            </p>

            <form action="<?php echo($self); ?>" method="POST">
                <p>
                    <input type="hidden" name="step" value="1">
                    <input type="submit" name="submit" value="Try Again">
                </p>
            </form>

            <?php
        }    // end of step 2

    include('includes/footer.php');
?>

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