PHP随机字符串Ascii

Question

I'm new at PHP and don't have any idea, why this doensn't works:

$lenght=32;
$startAscii=48;
$endAscii=122;

echo getString();

function getString() {
    $text="";

    for($count = 1; $count < $lenght; $count++) {
        $text=$text.chr(mt_rand($startAscii, $endAscii));
    }

    return $text;
}

He goes never into for loop. First, if I remove the $lenghth variable and hard code the number in the loop he goes inside. But then I don't get anything out of it.

Answer 1

It is because the function is using only local variables . You need do this:

function getString() {
    $text="";

    $length=32;
    $startAscii=48;
    $endAscii=122;

    for($count = 1; $count < $length; $count++) {
        $text=$text.chr(mt_rand($startAscii, $endAscii));
    }

    return $text;
}

Or you can do that, but this is more "uglier" solution:

function getString() {
    global $length, $startAscii, $endAscii;

    $text="";

    for($count = 1; $count < $length; $count++) {
        $text=$text.chr(mt_rand($startAscii, $endAscii));
    }

    return $text;
}

Or you can do it as parameters, which I think is best solution, because this function is more effective (you can use this function with different values without editing code inside):

function getString($length, $startAscii, $endAscii;) { ... }

$length=32;
$startAscii=48;
$endAscii=122;

echo getString($lenght, $startAscii, $endAscii);