print value of checked checkbox

if (isset($_POST['approve']))
{
    $con=mysql_connect("localhost","root","");
    mysql_select_db("shoolin",$con);
    $arr=$_POST['check'];
    foreach($arr as $selected)
    {
    echo $selected."</br>";
    }
}

i need to print the value of checkbox which is checked,so please suggest some solution to solve this problem of printing value of checkbox

This code shows an error in the foreach loop

Invalid argument supplied for foreach() in C:\xampp\htdocs\xampp\user.php on line 8