<?php
echo coding(6);
function coding($num){
	$str_arr = array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','0','1','2','3','4','5','6','7','8','9');
	$rand_s = array_rand($str_arr,$num);
	$code_s = '';
	if(is_array($rand_s)){
		foreach($rand_s as $v){
			$code_s .= $str_arr[$v];
		}
		return $code_s;
	}else{
		return $str_arr['rand_s'];
	}
}
?>