<?php

function generateAlphanumCode($length) {
        $charSet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
        $chars = preg_split("//",$charSet, -1, PREG_SPLIT_NO_EMPTY);
        $code = '';
        for ($i = 0; $i < $length; $i++) {
                $code .= $chars[random_int(0, count($chars) - 1)];
        }
        return $code;
}


print(generateAlphanumCode(6) . "\n");