reverse case

function reverseCase($string) {
  $length = strlen($string);
  for($i = 0; $i < $length; $i++) {
     if(ctype_upper ($string[$i])) {
       echo strtolower($string[$i]);
    } else {
       echo strtoupper($string[$i]);
    }
  }
}

reverseCase('hello Bangladesh');