About mt_rand()

Anon

What is seed value? What does it mean that mt_srand() 'seeds' mt_rand()? I just need to use this function and don't know exactly how it should be used.

Anon

Random numbers are not truly random. They are basically a list, and the seed controls where you start in that list. If you give it the same seed all of the time, you'll get the same sequence of "random" numbers. This is useful for debugging, so you can control the program.

The seed is usually based on the time (microtime with mt_rand) so that it's fairly unique for each visitor.

---John Holmes...

Anon

Thanks, now I can understand about seeding. But more question.
I have code:

mt_srand((double)microtime()*1000000);
$a=rand();

And it always returnes the same $a each time I enter the script. Why? How can I get the really random value?

Anon

Hi Hannchen,

mt_srand() seeds the function mt_rand() and not rand();

If you want to use rand(), then you have to seed it with srand();

I hope this helps

Anon

Yes! Thanks! It's my fault after a long working day :-)