help understanding this script...

Dutch_MaFia-boy

I'm learning php out of a book. I'm a little confused by the following script given in the book.....for starters, it doesn't work! - line 11 is giving me a error (which is the srand line). I'm also thinking that $string and $length are variables....right??

<html>
<head>
<title>Password Generator</title>
<body>
<?php
$string = "This is the text which will be encrypted so that we may create random and
secure passwords!";
$length = 8;
$string = md5($string);
$stringlength = strlen($string)
srand ((double) microtime() * 1000000);
$begin = rand(0,($stringlength-$length-1));
$password = sunstr($string, $begin, length);
print ("Your recommended password is:<p><big>$password</big></b>\n");
?>
</body>
</html>

zhabala

There is a semicolon missing on previous line. The one with strlen.

Zdenek

LeZeNkO

Which book?

Dutch_MaFia-boy

Which book?

PHP for the World Wide Web

by Larry Ullman. Its from the visual quickstart series....

Yamakazi

Here we go:

<?php
/* $string is a variable and text is put in*/
$string = "This is the text which will be encrypted so that we may create random and 
secure passwords!"; 
/* $lenght is another variable assigned the value 8*/
$length = 8; 
/*The md5 hash of the string is assigned to the string itself
   so string contains the value  ac77889dbf3dedabec0c7c42b00d7c4e (if you don't know what a md5 is check google*/
$string = md5($string);  

/* We check how much characters the $string has, wich is kinda silly because a md5 has always 32 */
$stringlength = strlen($string); 
/*This isn't needed anymore as from 4.2.0 */
srand ((double) microtime() * 1000000); 
/* This will put a random number from 0 to 23 in 
    why 23 because as we now $stringlength is always 32
    $lenght is a constant 8
   32 - 8 - 1 = 23
*/
$begin = rand(0,($stringlength-$length-1)); 
/*You will take a sub string from $string which begins at $begin and wich has the lenght of $lenght
So basicly what this script does is take 8 characters from the md5 hash ac77889dbf3dedabec0c7c42b00d7c4e and prompt it as a random password. 
*/

$password = substr($string, $begin, $length); 
print ("Your recommended password is:<p><big>$password</big></b>\n"); 
?>

Actually this script kinda sucks as it can only make 24 different passwords. So that ain't very random.

hope that helped