passing the reference of the function as an argument
<p>How can I pass the reference of a function to another function as an argument ? I was trying to implement a callback and I need to pass the reference of the function <code>returnProduct</code> before.How do I do that ?</p>

<pre><code>&lt;?php
class Tester {
    public function calculate($var_1,$var_2,$var_3) {
        $product = var_3($var_1,$var_2);
        echo $product;
    }

    public function returnProduct($var_1,$var_2) {
        return $var_1*$var_2;   
    }
}

$obj = new Tester();
$obj-&gt;calculate(100,2,$obj-&gt;returnProduct);
</code></pre>
