Cyrillic script not working?

Question

PHP

There is a script
<?php
function generatePassword($length = 8){
$chars = 'yutsu';
$numChars = strlen($chars);
$string = '';
for ($i = 0; $i < $length; $i++) {
$string .= substr($chars, rand(1, $numChars) - 1, 1);
}
return $string;
}
$n = "" . generatePassword(8) . "\n";
echo iconv_mime_encode('blabla: ', $n, array('input-charset' => 'UTF-8', 'output-charset' => 'windows-1251'));
?>
Here's a script whose output doesn't work. There are no errors, but nothing is displayed (as if there is no echo)
BUT if you replace $chars with English characters (qwer ...) - everything will work fine.
What is the problem that it does not work with Cyrillic and how to make it work with ru characters?
Thanks in advance

Answer 1

See the doc for mb_strlen and mb_substr. Your problem is that Cyrillic in utf-8 has 2 bytes per character, while strlen and substr only work for 1-byte characters.

Answer 2

It might make sense to take a look here: php.net/manual/en/book.mbstring.php

Answer 3

mb_strlen