could some one look at this function for me? Thx ;]

[Jim303]

Hi guys was wondering if any you out there would know why this function doesnt generate a 8 character long string everytime... sometimes its 7 sometimes its 6.... would really appreciate any help ;]

function createRandomPassword() {

$chars = "abcdefghijkmnopqrstuvwxyz";
srand((double)microtime()*1000000);
$i = 0;
$pass = '' ;

while ($i <= 8) {
    $num = rand() % 33;
    $tmp = substr($chars, $num, 1);
    $pass = $pass . $tmp;
    $i++;
}

return $pass;

}

[scrupul0us]

instead of:

$num = rand() % 33;

use:
$num = rand(1,26) ;

[Jim303]

Thanks a million for that!! Just learnt a new php command rand() ;] ;] Had to tweak it just slightly as of the missing L from the alphabet.

Working code:

function createRandomPassword() {

$chars = "abcdefghijkmnopqrstuvwxyz";
srand((double)microtime()*1000000);
$i = 0;
$pass = '' ;

while ($i < 8) {
    $num = rand(1,24);
    $tmp = substr($chars, $num, 1);
    $pass = $pass . $tmp;
    $i++;
}

return $pass;

}

[laserlight]

I suggest using a for loop instead of a while loop, and using mt_rand() instead of rand(). You dont need to seed the pseudorandom number generator as it should be seeded for you. You could make the string of valid characters static. Since you might want to add more characters to the list of valid characters, calculating the size of the list would avoid having a magic constant in the function.

function createRandomPassword($len = 8) {
	// string of valid password characters
	static $chars = "abcdefghijkmnopqrstuvwxyz";
	// find maximum index of valid password char string
	$chars_max = strlen($chars) - 1;
	// generate password
	$password = '';
	for ($i = 0; $i < $len; ++$i) {
		$password .= $chars{mt_rand(0, $chars_max)};
	}
	return $password;
}

[Installer]

use:
$num = rand(1,26) ;

The offset starts at 0, so this would work better:

$num = rand(0,26) ;

Here's a function that's simpler than the original and more flexible:

function createRandomPassword($len = 8, $use_uc = false, $use_digits = false) 
{
    $chars = range('a', 'z');
    if ($use_uc) {
        $chars = array_merge($chars, range('A', 'Z'));
    }
    if ($use_digits) {
        $chars = array_merge($chars, range('0', '9'));
    }
    $max_offset = count($chars) - 1; 
    $pass = '' ;
    for ($i = 0; $i < $len; $i++) {
        $offset = mt_rand(0, $max_offset);
        $pass .= $chars[$offset];
    }
    return $pass;
}

[Jim303]

Thanks laserlight & installer;] Have to say installer that function kicks ass!! Cheers for posting learnt a bunch of new stuff ;]

[jeditdog]

that is a killer function.

(thanks, I don't usually read through forums, but this proved very informative)