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Groups > comp.lang.c > #28441

Re: time

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: time
Date 2012-11-19 16:30 -0800
Organization None to speak of
Message-ID <lnsj85f753.fsf@nuthaus.mib.org> (permalink)
References <k8ehrs$ddf$1@dont-email.me>

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"Bill Cunningham" <nospam@nspam.invalid> writes:
>     I am using the time and date in my code using asctime () time(), and 
> localtime(). I know in POSIX they are obsolete but I am concerned with 
> c89-99. strftime() is suppoed to be the function used now. I get the time 
> and date just fine with the code I've written but I want to use the time to 
> seed a random number generator. I don't know if I want seconds from epoch or 
> what. Any input?

strftime() has been in the C standard since 1989.

A typical way to seed the standard random number generator is:

    srand(time(NULL));

There are some drawbacks to this approach, discussed in the FAQ,
<http://www.c-faq.com/>.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
    Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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Thread

time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-19 19:11 -0500
  Re: time Geoff <geoff@invalid.invalid> - 2012-11-19 16:26 -0800
    Re: time Keith Thompson <kst-u@mib.org> - 2012-11-19 16:51 -0800
      Re: time Geoff <geoff@invalid.invalid> - 2012-11-19 17:01 -0800
      Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-19 20:07 -0500
        Re: time Keith Thompson <kst-u@mib.org> - 2012-11-19 23:54 -0800
          Re: time pete <pfiland@mindspring.com> - 2012-11-20 07:31 -0500
          Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-20 17:09 -0500
  Re: time Keith Thompson <kst-u@mib.org> - 2012-11-19 16:30 -0800
    Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-19 20:04 -0500
      Re: time Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-11-25 05:52 -0800
  Re: time Nobody <nobody@nowhere.com> - 2012-11-20 03:07 +0000
    Re: time Keith Thompson <kst-u@mib.org> - 2012-11-19 23:58 -0800
    Re: time Anand Hariharan <mailto.anand.hariharan@gmail.com> - 2012-11-21 08:30 -0800
      Re: time "osmium" <r124c4u102@comcast.net> - 2012-11-21 11:11 -0600
      Re: time James Kuyper <jameskuyper@verizon.net> - 2012-11-21 12:22 -0500
        Re: time gof@somewhere.invalid (Adam Wysocki) - 2012-11-21 19:09 +0000
          Re: time Keith Thompson <kst-u@mib.org> - 2012-11-21 12:01 -0800
            Re: time gof@somewhere.invalid (Adam Wysocki) - 2012-11-23 08:15 +0000
          Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-21 15:16 -0500
            Re: time "osmium" <r124c4u102@comcast.net> - 2012-11-21 14:23 -0600
              Re: time Rosario1903 <Rosario@invalid.invalid> - 2012-11-22 10:25 +0100
            Re: time Keith Thompson <kst-u@mib.org> - 2012-11-21 12:30 -0800
              Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-21 18:24 -0500
            Re: time Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-11-25 05:56 -0800
          Re: time Nobody <nobody@nowhere.com> - 2012-11-22 02:00 +0000
            Re: time Keith Thompson <kst-u@mib.org> - 2012-11-21 19:57 -0800
              Re: time gof@somewhere.invalid (Adam Wysocki) - 2012-11-23 08:31 +0000
            Re: time army1987 <army1987@ask-for-it.invalid> - 2012-11-24 13:58 +0000
          Re: time Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-22 11:36 +0000
            Re: time gof@somewhere.invalid (Adam Wysocki) - 2012-11-23 08:20 +0000
              Re: time Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-11-23 14:31 +0000
      Re: time Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-11-25 05:54 -0800
  Re: time Mark Storkamp <mstorkamp@yahoo.com> - 2012-11-20 08:34 -0600
    Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-20 20:37 -0500
      Re: time Keith Thompson <kst-u@mib.org> - 2012-11-20 20:25 -0800
        Re: time "Bill Cunningham" <nospam@nspam.invalid> - 2012-11-21 15:11 -0500

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