Random numbers in PHP

**cursedpsp** · 05-05-2008 08:47 AM

Hi, ill show you how to use 'mt_rand' 'srand' and a really complicated one that makes hexadecimal numbers.

lets start off with the 'mt_rand' function.

Code:

//Minimum number
$min = 1;
 
//Maximum number
$max = 100;
 
//Put mt_rand into a variable
$random = mt_rand($min, $max);
 
echo "Our random number of the day is: " . $random;

Now for the 'srand' function.

Code:

//Minimum number
$min = 1;
 
//Maximum number
$max = 100;
 
srand((double) microtime()*1000003);
//1000003 because it is a prime number
 
//convert it to a variable
$random = rand($min, $max);
 
echo "Another random number today is: " . $random

I dont actually know what the difference it to the random number functions but they do their job

.

The next one will create a hexadecimal code which is very useful for sessions and cookies, so that people will never guess them!

Code:

$hex = sha1(uniqid(mt_rand()));
 
echo "Todays impossible to guess hex code is: " . $hex;

echo

**cursedpsp** · 05-26-2008 05:52 AM

There is a way to increase the hex digits but i dont know how to - anyone?

**hamsn** · 05-27-2008 02:04 AM

where will this be useful?
i mean like can we use it in visitor counter
no. of seconds logged in

or else...ideas?

**marshian** · 05-27-2008 11:14 AM

I don't think this is really a good tutorial to be honest...
mt_rand() is just a function like rand(), you need 30 seconds to look it up at php.net...
And about the second srand() and rand() thing...
http://be.php.net/manual/en/function.srand.php
"Note: As of PHP 4.2.0, there is no need to seed the random number generator with srand() or mt_srand() as this is now done automatically."
So you don't need to call srand() at all...
And sha1() is just a form of encoding stuff, using the secure hash algorithm 1, it has nothing to do with random numbers...

Sorry, but if you make a tutorial, please inform yourself properly...