PHP 生成随机数

function randPassword()
{
$num_len = $str_len = mt_rand(3,6);
$num = '0123456789';
$str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_';
$num = randChar($num_len, $num);
$str = randChar($str_len, $str);
return str_shuffle($num.$str);
}




function randName()
{
$num_len = mt_rand(3,6);
$str_len = mt_rand(6,12);
$num = '0123456789';
$str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_';
$num = randChar($num_len, $num);
$str = randChar($str_len, $str);
return str_shuffle($num.$str);
}




function randChar($length, $strPol='')
{
$str = null;
$strPol = $strPol ? : "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz_";
$max = strlen($strPol)-1;
for($i=0;$i<$length;$i++){
$str.=$strPol[rand(0,$max)];//rand($min,$max)生成介于min和max两个数之间的一个随机整数
}

return $str;

}

                    未完待续......