随机字符串生成器使字符串长度错误（PHP）

Question

I'm trying to make a function that generates a random string, but the string is sometimes the wrong length.

function getRandomName($maxChars)
{
    $nameChars = str_split("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890");
    $numOfChars = count($nameChars); // amount of characters in $nameChars
    $randomString = "";
    for($count=0;$count<$maxChars;$count++)
    {
        $randomInt = round(rand(0,$numOfChars));
        $selectedChar = $nameChars[$randomInt]; // random character in $nameChars
        $randomString .= $selectedChar; // adds to string
    }
    echo " ".strlen($randomString).", "; // length, string is echoed later
    return $randomString;
}
exit(getRandomName(6)); // 6 characters long

?>

Most of the time, the result will be something like 6, s2jd8q. But sometimes, the result is something like 5, d82kw. I only want strings that are 6 characters long, not 5. Anyone know how to fix this?

Answer 1

Edit $randomInt = round(rand(0,$numOfChars)); to $randomInt = round(rand(0,$numOfChars-1));

If you run this

$nameChars = str_split("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890");
$numOfChars = count($nameChars); // amount of characters in $nameChars
//$numOfChars = 62

echo($nameChars[61]); //Output: 0 (Last character)