Custom module: JSession brokes the site

Question

I am making custom shop module for my website and my script breakes all pages where it is. The command what breaks it is: $session =& JFactory::getSession(); (Code putted in default.php). I cant put this in helper as i update the value and i need the updated one. So what i mean with breaks, the template gets broken and leaves the module only. Thank you.

EDIT: The code

$session =& JFactory::getSession();

if($_GET['additem'] != ""){
    for($i = 0; $i < count($items); $i++){
        if($items[$i][0] == $_GET['additem']){
            $id = $i;
        }
    }

    $cart = $session->get('cart', array());
    $cart[count($cart)] = $id;

    $session->set('cart', $cart);
}else{

    $cart = $session->get('cart', array());

}

echo "<table class='table table-hover'>";
    echo '<tr>';
        echo '<th>Id</th>';
        echo '<th>Name</th>';
        echo '<th>Price</th>';
    echo '</tr>';

    for($i = 0; count($cart); $i++){
        echo '<tr>';
            echo '<td>' . $items[$cart[$i]][0] . '</td>';
            echo '<td>' . $items[$cart[$i]][1] . '</td>';
            echo '<td>' . $items[$cart[$i]][2] . '</td>';
        echo '</tr>';
    }

echo '</table>';

Answer 1

Infinite for loop...

for($i = 0; count($cart); $i++){

should be

for($i = 0; $i < count($cart); $i++){

Forgot the $i < count.