odd even tr color

$j = 0;
foreach ($student_notes as $i => $value) {
$j = ($j == 0) ? 1 : 0;
$bg_color = ($j == 0) ? “” : “bgcolor=’#f5f5f5′”;
$updatedBy = Admin::getAdminUserById($value[‘updated_by’]);
?>
<tr <?php echo $bg_color; ?>>