Compare two version strings in PHP
<p>How to compare two strings in version format? such that: </p>

<pre><code>version_compare("2.5.1",  "2.5.2") =&gt; -1 (smaller)
version_compare("2.5.2",  "2.5.2") =&gt;  0 (equal)
version_compare("2.5.5",  "2.5.2") =&gt;  1 (bigger)
version_compare("2.5.11", "2.5.2") =&gt;  1 (bigger, eleven is bigger than two)
</code></pre>
