Re: Best way to get a non-repeating random number?
Re: Best way to get a non-repeating random number?
- Subject: Re: Best way to get a non-repeating random number?
- From: Uli Kusterer <email@hidden>
- Date: Tue, 14 Apr 2009 01:57:19 +0200
On 14.04.2009, at 01:44, Luca C. wrote:
You can put every (unsigned) value you want in there, though in
general it's used passing (unsigned)time(NULL) as parameter. This way
you'll always get a different int.
No you won't. It's a *random* number generator. The seed simply
means you get a different sequence of random numbers. However, random
really means RANDOM. I.e. it's perfectly possible to get the same
number three times in a row during a sequence. That would still be
random.
I think it would be best if Eric told us what he's trying to do. For
example, in some cases, (e.g. sorting) you actually want to build a
new list and shuffle that by returning random numbers from your sort
function. In that case, since your list only contains each item once,
and your random numbers only affect their order, it's perfectly OK to
just return a random number. You'll still get a shuffled list with
each item only once.
OTOH, in other cases, you might actually have to do the looping
thing and just keep asking for a new random number until you get one
that isn't the previous number.
Cheers,
-- Uli Kusterer
"The Witnesses of TeachText are everywhere..."
http://www.zathras.de
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