Date: Tue, 16 Feb 1999 22:09:31 -0800 From: Josef Grosch <jgrosch@mooseriver.com> To: Patrick Seal <patseal@hyperhost.net>, freebsd-questions@FreeBSD.ORG Subject: Re: Random Numbers Message-ID: <19990216220931.B5145@mooseriver.com> In-Reply-To: <Pine.BSF.4.05.9902162134210.809-100000@foobar.hyperhost.net>; from Patrick Seal on Tue, Feb 16, 1999 at 09:36:40PM -0500 References: <Pine.BSF.4.05.9902162134210.809-100000@foobar.hyperhost.net>
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On Tue, Feb 16, 1999 at 09:36:40PM -0500, Patrick Seal wrote:
> In this the best way to get a number from one to ten in C:
>
> #include <stdlib.h>
>
> randn(float value) {
> value = random() * value / 2147483648.0;
> return(value);
> }
>
> n = randn(10.0) + 1
>
> printf("%i", n);
>
> I realize it's platform dependent. Is there a better way?
You should seed the random number generator first. Try the following;
int randn()
{
int rc = 0;
pid_t pid = getpid();
time_t now = 0;
long value = 0L;
unsigned long seed = 0L;
struct timeval tp;
struct timezone tzp;
gettimeofday(&tp, &tzp);
now = tp.tv_sec; /* unnecessary but nice during debugging */
seed = (unsigned long)(now / pid);
srandom(seed);
value = random();
rc = (value % 10);
return (rc);
}
This is OK for a quick hack. Play around with it. You should also consult
the man pages for random
Josef
--
Josef Grosch | Another day closer to a | FreeBSD 3.0
jgrosch@MooseRiver.com | Micro$oft free world | UNIX for the masses
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