line of codes in php
<p>Below is the code...help me in understanding the below codes of line...</p>

<pre><code>if (isset($_POST['register'])) {
    $error = array();

    if (!in_array(strtolower($_POST['captcha']), $aCaptcha[$_SESSION['captcha']])) {
        $error['captcha'] = "&lt;span style='color:red'&gt;The name of the animal is not correct.&lt;/span&gt;";
    }
    if (count($error) == 0) {
        //no errors, do other actions here, like saving into database, send email or...
        echo "&lt;span style='color:red'&gt;Thank you for completing the form.
We shall contact you soon.&lt;/span&gt;";
        die();
</code></pre>
