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Message-ID: <5b70945805031201261b6beac1@mail.gmail.com>
Date: Sat, 12 Mar 2005 10:26:24 +0100
From: Brian Budge <brian DOT budge AT gmail DOT com>
Reply-To: Brian Budge <brian DOT budge AT gmail DOT com>
To: Alex Vinokur <alexvn AT users DOT sourceforge DOT net>
Subject: Re: g++ & rand() in Cygwin
Cc: gcc-help AT gcc DOT gnu DOT org, cygwin AT cygwin DOT com
In-Reply-To: <d0u0pt$aj0$1@sea.gmane.org>
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References: <d0u0pt$aj0$1 AT sea DOT gmane DOT org>

Hi Alex -

You should seed the rng first before using it.  Also, there are much
better rngs out there than rand (though it's much better than it used
to be).  I tend to plug for  Mersenne Twister which is both faster,
produces better random numbers, and can be used in a parallel
programming environment.

  Brian


On Sat, 12 Mar 2005 08:04:59 +0200, Alex Vinokur
<alexvn AT users DOT sourceforge DOT net> wrote:
> ------ foo.cpp ------
> #include <cstdlib>
> #include <iostream>
> using namespace std;
> int main ()
> {
>   cout << rand() << endl;
>   cout << rand() << endl;
>   return 0;
> }
> ---------------------
> 
> // g++ version 3.3.3 (cygwin special)
> 
> $ g++ foo.cpp
> 
> The program below generates the following output:
> -----------
> 0
> 1481765933
> -----------
> 
> First pseuso-random number is 0.
> 
> Is it by purpose?
> 
> --
>  Alex Vinokur
>      email: alex DOT vinokur AT gmail DOT com
>      http://mathforum.org/library/view/10978.html
>      http://sourceforge.net/users/alexvn
> 
>

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