Cheat Engine

Aikos · Cheater Reputation: 0 Joined: 26 Nov 2007 Posts: 47

Hi all. I am writing a card game program, and now I am working on the shuffling of the deck. I have found the Fisher-Yates Algorithm that can shuffle a deck pretty efficiently (according to wikipedia), but it says I need an unbiased randomization. Although I know I can do the srand(time(NULL)); way in C, but I am not sure if it really gives unbiased results. Any help is appreciated and thanks in advance.

Dark Byte · Posted: Sat May 17, 2008 9:04 am Post subject:

they never give unbiased results.
Best ones you can get are those that take 2 months of calculations to come up with a semi-random value.

But for normal use srand is random enough. For someone to abuse it they'd need to know exactly how many times rand is called before the result is actually used. And calling rand a couple of times (e.g rand times) it makes it harder to guess.

Of course, there's always some fun tools like ce's unrandomizer that can really mess those things up

Aikos · Cheater Reputation: 0 Joined: 26 Nov 2007 Posts: 47

Thanks DB. The info is very helpful.

4ng3licDew · Cheater Reputation: 0 Joined: 14 Feb 2008 Posts: 28

You can read more about pseudorandom number generator from wikipedia:
http://en.wikipedia.org/wiki/Pseudorandom_number_generator

I have used the pseudo random generator developed by Makoto Matsumoto for my chess program. I needed the random numbers for my Zobrist keys (http://chessprogramming.wikispaces.com/Zobrist+Hashing).

You can get the C source code for the pseudo random generator from here:
http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html

Please note: This pseudorandom number generator is not cryptographically secure "as is". Please read FAQ from Mersenne Twister Home Page:
http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html