Robert van Herk wrote,
Hello all,
Is it possible to generate random numbers that are "unique" in O(1) in Haskell?
I mean something like the GUID-thingy Windows uses.
Of course, I could create unique numbers by incrementing a global value, but for security reasons I need random numbers. Also, I could use a list of numbers already in use, but this would mean that I'd not be able to generate a new number in O(1).
There are standard algorithms for doing this job, and it might be better to use one of them rather than reinventing the wheel. See here, http://www.itu.int/ITU-T/asn1/uuid.html or possibly here, http://www.ietf.org/internet-drafts/draft-mealling-uuid-urn-05.txt Open source implementations in a variety of (imperative) languages and with a variety of licenses are available via google. There's also one in J2SE 5.0. Cheers, Miles