Simple function in PHP with Calculation
<p>I am making very simple program in PHP . Tryig to addition first ..</p>

<p>But dont know .. </p>

<p>Here is code </p>

<pre><code>&lt;?php 
$a=12;
$b=10;
$c="+";

$res=$a."$c".$b;
echo $res;
?&gt;
</code></pre>

<p>it output 12+10 as it is concecate.. </p>

<p>$c is anything.</p>

<p>Any idea how to do this</p>
