Re: Another little puzzle

From	Richard Heathfield <rjh@cpax.org.uk>
Newsgroups	comp.programming
Subject	Re: Another little puzzle
Date	2022-12-14 14:10 +0000
Organization	Fix this later
Message-ID	<tnclg3$2of9o$2@dont-email.me> (permalink)
References	<puzzle-20221214131815@ram.dialup.fu-berlin.de> <tncho3$ilr$1@gioia.aioe.org> <tnci0u$2of9h$3@dont-email.me> <tncjem$19kh$1@gioia.aioe.org>

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On 14/12/2022 1:35 pm, Dmitry A. Kazakov wrote:
> On 2022-12-14 14:10, Richard Heathfield wrote:
>> On 14/12/2022 1:06 pm, Dmitry A. Kazakov wrote:
>>> On 2022-12-14 13:24, Stefan Ram wrote:
>>>>    Given n times of the 24-hour day, print their average.
>>>>
>>>>    For example, the average of "eight o'clock" and
>>>>    "ten o'clock" (n=2) would be "nine o'clock".
>>>
>>> You probably missed to require the interesting part: doing all 
>>> that in the modular type (modulo 24) arithmetic:
>>>
>>>     20 + 5 = 1 (mod 24)
>>
>> ...which will give you the wrong answer. Chase that goose!
> 
> Right, you must count the wrap-ups.

No, you don't. You're given n times of the 24-hour day, so all 
values are already in the hour range [0-24). Convert to seconds 
from midnight, add all values, divide by n to give a number t 
guaranteed (assuming no leap seconds) to be in the range 
[0-86400), and convert to the representation of your choice. (And 
even if there is a leap second, it doesn't matter more than half 
a sixpence.)

e.g.

int h, m, s;

h = t / 3600;
m = (t - h*3600) / 60;
s = (t - h*3600 - m * 60);

So why do you need mod?

-- 
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

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Re: Another little puzzle "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2022-12-14 14:06 +0100
  Re: Another little puzzle Richard Heathfield <rjh@cpax.org.uk> - 2022-12-14 13:10 +0000
    Re: Another little puzzle "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2022-12-14 14:35 +0100
      Re: Another little puzzle Richard Heathfield <rjh@cpax.org.uk> - 2022-12-14 14:10 +0000
        Re: Another little puzzle "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2022-12-14 15:58 +0100
          Re: Another little puzzle Richard Heathfield <rjh@cpax.org.uk> - 2022-12-14 15:18 +0000
            Re: Another little puzzle "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2022-12-14 16:41 +0100
              Re: Another little puzzle "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2022-12-14 16:43 +0100
                Re: Another little puzzle Y A <angel00000100000@mail.ee> - 2023-01-09 16:33 -0800
              Re: Another little puzzle Richard Heathfield <rjh@cpax.org.uk> - 2022-12-14 16:13 +0000
        Re: Another little puzzle V <angleeeeeeee@mail.ee> - 2023-05-10 11:16 -0700
    Re: Another little puzzle Ǝ <angel0000000001000000000000@mail.ee> - 2022-12-30 05:59 -0800

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