Re: Another little puzzle

From	Richard Heathfield <rjh@cpax.org.uk>
Newsgroups	comp.programming
Subject	Re: Another little puzzle
Date	2022-12-14 15:18 +0000
Organization	Fix this later
Message-ID	<tncpgk$2of9h$7@dont-email.me> (permalink)
References	(1 earlier) <tncho3$ilr$1@gioia.aioe.org> <tnci0u$2of9h$3@dont-email.me> <tncjem$19kh$1@gioia.aioe.org> <tnclg3$2of9o$2@dont-email.me> <tncob5$1oat$1@gioia.aioe.org>

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On 14/12/2022 2:58 pm, Dmitry A. Kazakov wrote:
> On 2022-12-14 15:10, Richard Heathfield wrote:
>> 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.
> 
> [...]
> 
>> So why do you need mod?
> 
> As I said, the challenge is only interesting in modulo arithmetic

So the challenge is only interesting if you add something you 
don't need. Let's throw in some elephants. Does that make it more 
interesting?

> BTW, averaging floats is a nasty problem too. A naive 
> implementation quickly loses precision.

We're dealing with 'o'clock' and "HH:MM", and nowadays we have 
64-bit integer types and there are even 128-bit integers mooching 
around looking for a reason to exist. You'd have to average a 
hell of a lot of times even to /need/ floats, let alone lose 
significant precision.

-- 
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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