How to force PHP to output a number preceded by zeros?
<p>for ($number = 1; $number &lt;= 16; $number++) {
        echo $number . "\n";
    }</p>

<p>This code outputs:</p>

<pre><code>1
2
3
...
16
</code></pre>

<p>How can I get PHP to output the numbers preceded by zeros?</p>

<pre><code>01
02
03
...
16
</code></pre>
