Removing everything after specific character
<p>I'm developing a Qt application. I have some Strings like :</p>

<p>(Sub String before @)</p>

<pre><code>43243263@example.com

325754754@example.com
</code></pre>

<p>I want to use </p>

<pre><code>43243263

325754754
</code></pre>

<p>How to do that?</p>