Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.c > #41685

Re: c prog -plz explain

From Ian Collins <ian-news@hotmail.com>
Newsgroups comp.lang.c
Subject Re: c prog -plz explain
Date 2014-03-13 09:38 +1300
Message-ID <bobuuuFbpi1U5@mid.individual.net> (permalink)
References (4 earlier) <20140310235955.176@kylheku.com> <lfpa7b$150$1@dont-email.me> <20140312073525.267@kylheku.com> <lfqbl5$it2$1@speranza.aioe.org> <lfqeli$qls$1@dont-email.me>

Show all headers | View raw


Eric Sosman wrote:
> On 3/12/2014 3:13 PM, glen herrmannsfeldt wrote:
>> Kaz Kylheku <kaz@kylheku.com> wrote:
>>> On 2014-03-12, Noob <root@127.0.0.1> wrote:
>>
>> (snip)
>>>> Ergo, a simple rule for beginners would be: "Don't use casts anywhere".
>>
>> (snip)
>>
>>> What if you're calculating  i / j, where i and j are integers, and you
>>> want an answer like 2.75?
>>
>>> No i / (double) j for you; stick with two?  :)
>>
>>> The stupid thing is that completely bat-shit unsafe stuff shares
>>> the same notation with necessary conversions.
>>
>> Well, first, I agree, but sometimes there are ways around it.
>>
>> If you want percentage, you can:
>>
>>      pct=100.*i/j;
>>
>> no cast needed, because the multiply will force the conversion.
>
>       ObPuzzle: Which of the `return' statements below is the best,
> and why?
>
> 	#include <time.h>
> 	/**
> 	 * Find how many CPU seconds were consumed between
> 	 * two values returned by clock().
> 	 */
> 	double cpuSeconds(clock_t t0, clock_t t1) {
> 	    /* A */ return (t1 - t0) / CLOCKS_PER_SEC;
> 	    /* B */ return (t1 - t0) / (double) CLOCKS_PER_SEC;
> 	    /* C */ return (t1 - t0) / (CLOCKS_PER_SEC + 0.0);
> 	}
>

Or Option D

double cpuSeconds(clock_t t0, clock_t t1) {
   static const double clocksPerSec = CLOCKS_PER_SEC;
   return (t1 - t0) / clocksPerSec;
}

-- 
Ian Collins

Back to comp.lang.c | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

c prog -plz explain SAHIL MAHLA <sahilmehla@gmail.com> - 2014-03-10 14:50 -0700
  Re: c prog -plz explain Keith Thompson <kst-u@mib.org> - 2014-03-10 15:41 -0700
    Re: c prog -plz explain Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-03-10 23:21 +0000
      Re: c prog -plz explain Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-03-10 23:24 +0000
      Re: c prog -plz explain SAHIL MAHLA <sahilmehla@gmail.com> - 2014-03-10 20:28 -0700
        Re: c prog -plz explain James Kuyper <jameskuyper@verizon.net> - 2014-03-11 00:15 -0400
        Re: c prog -plz explain Kaz Kylheku <kaz@kylheku.com> - 2014-03-11 07:12 +0000
          Re: c prog -plz explain Noob <root@127.0.0.1> - 2014-03-12 10:43 +0100
            Re: c prog -plz explain Kaz Kylheku <kaz@kylheku.com> - 2014-03-12 14:38 +0000
              Re: c prog -plz explain Noob <root@127.0.0.1> - 2014-03-12 15:56 +0100
                Re: c prog -plz explain Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-03-12 11:16 -0400
                Re: c prog -plz explain James Kuyper <jameskuyper@verizon.net> - 2014-03-12 11:36 -0400
                Re: c prog -plz explain Kaz Kylheku <kaz@kylheku.com> - 2014-03-12 15:38 +0000
              Re: c prog -plz explain glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-12 19:13 +0000
                Re: c prog -plz explain Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-03-12 16:05 -0400
                Re: c prog -plz explain James Kuyper <jameskuyper@verizon.net> - 2014-03-12 16:32 -0400
                Re: c prog -plz explain Ian Collins <ian-news@hotmail.com> - 2014-03-13 09:38 +1300
                Re: c prog -plz explain Tim Rentsch <txr@alumni.caltech.edu> - 2014-03-29 08:32 -0700
            Re: c prog -plz explain glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-12 19:03 +0000
              Re: c prog -plz explain James Kuyper <jameskuyper@verizon.net> - 2014-03-12 15:33 -0400
                Re: c prog -plz explain Kaz Kylheku <kaz@kylheku.com> - 2014-03-12 20:56 +0000
                Re: c prog -plz explain Ian Collins <ian-news@hotmail.com> - 2014-03-13 10:07 +1300
        Re: c prog -plz explain "BartC" <bc@freeuk.com> - 2014-03-11 10:33 +0000
  Re: c prog -plz explain Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2014-03-10 18:48 -0400
    Re: c prog -plz explain SAHIL MAHLA <sahilmehla@gmail.com> - 2014-03-10 20:26 -0700
      Re: c prog -plz explain Ian Collins <ian-news@hotmail.com> - 2014-03-11 16:34 +1300
        typecasting (was Re: c prog -plz explain) Jorgen Grahn <grahn+nntp@snipabacken.se> - 2014-03-12 07:03 +0000
          Re: typecasting (was Re: c prog -plz explain) Kaz Kylheku <kaz@kylheku.com> - 2014-03-12 07:40 +0000
            Re: typecasting (was Re: c prog -plz explain) Lowell Gilbert <lgusenet@be-well.ilk.org> - 2014-03-12 10:47 -0400
            Re: typecasting (was Re: c prog -plz explain) Ken Brody <kenbrody@spamcop.net> - 2014-03-12 13:01 -0400
          Re: typecasting (was Re: c prog -plz explain) Richard <rgrdev_@gmail.com> - 2014-03-12 12:47 +0100
            Re: typecasting (was Re: c prog -plz explain) gazelle@shell.xmission.com (Kenny McCormack) - 2014-03-12 12:39 +0000
              Re: typecasting (was Re: c prog -plz explain) Kaz Kylheku <kaz@kylheku.com> - 2014-03-12 15:06 +0000
      Re: c prog -plz explain Kaz Kylheku <kaz@kylheku.com> - 2014-03-11 07:26 +0000
        Re: c prog -plz explain Richard <rgrdev_@gmail.com> - 2014-03-11 08:39 +0100
          Re: c prog -plz explain Kaz Kylheku <kaz@kylheku.com> - 2014-03-11 08:08 +0000
      Re: c prog -plz explain Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2014-03-11 09:14 -0400
      Re: c prog -plz explain Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-03-11 15:38 +0000
  Re: c prog -plz explain Ken Brody <kenbrody@spamcop.net> - 2014-03-11 12:53 -0400
    Re: c prog -plz explain Keith Thompson <kst-u@mib.org> - 2014-03-11 11:47 -0700
      Re: c prog -plz explain glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-03-11 21:41 +0000
        Re: c prog -plz explain Kaz Kylheku <kaz@kylheku.com> - 2014-03-11 22:01 +0000

csiph-web