PHP产生随机密码的函数

<?
function MakePass($length)
{
$possible = “0123456789!@#$%^&*()_+”.
             “abcdefghijklmnopqrstuvwxyz”.
             “ABCDEFGHIJKLMNOPQRSTUVWXYZ”;
$str = “”;
while(strlen($str) < $length)
{
  $str .= substr($possible, (rand() % strlen($possible)), 1);
}
return($str);
}
?>