What does & in &$data do?
<p>A quick beginner's question in PHP.</p>

<p>What does &amp; in &amp;$data do and what are differences with $data?</p>

<pre><code>function prepareMenu(&amp;$data) {
 $this-&gt;db-&gt;where('parentid',0)
...
...
</code></pre>
