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Re: C o m p e t i t i o n .

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On 15/01/2021 01:23, Ben Bacarisse wrote:
> Peter 'Shaggy' Haywood <phaywood@alphalink.com.au> writes:
> 
>> Groovy hepcat Richard Heathfield was jivin' in comp.programming on Thu,
>> 14 Jan 2021 07:01 am. It's a cool scene! Dig it.
>>
>>> On 13/01/2021 10:31, Y A wrote:
>>>> Richard Heathfield kirjutas kolmapäev, 13. jaanuar 2021 kl 11:14:09
>>>> UTC+2:
>>>>> On 12/01/2021 23:25, Y A wrote:
>>>>>> Richard Heathfield kirjutas teisipäev, 12. jaanuar 2021 kl 18:17:01
>>>>>> UTC+2:
>>>>>>> On 12/01/2021 13:17, I I wrote:
>>>>>>>
>>>>>>> <snip>
>>>>>>>> I am so sorry, that You have not attended school . . . . . .
>>>>>>> Irony is always amusing, but the more so when unintentional.
>>>>>>
>>>>>> Hmmmmmmmmmmmmmmmmmmmm...........................
>>>>>> Cross sum isn't logically: sum of all digits?
>>>>>> abcde cs=a+b+c+d+e
>>>>> I'd never heard the term before the OP used it at the beginning of
>>>>> this thread, so I looked it up.
>>>>>
>>>>> The only meaning I could find for it online was "sum of all digits"
>>>>> (i.e. the digital root), so I calculated the sum of all digits.
>>>>>
>>>>> Presumably the OP (who has a different result) means something
>>>>> different by it, but he appears unwilling to share that meaning with
>>>>> us.
>>>>
>>>> OP=me
>>>
>>> Then you ought to know what you mean by "cross sum", so you ought to
>>> be in a position to share that information.
>>>
>>> If you mean "digital root", I've already given the correct answer,
>>> which you say is different to your answer, which means you're wrong.
>>
>>   Just to add my two cents to this discussion, for what it's worth
>> (somewhere between one and three cents, presumably), I wrote, compiled
>> and ran the following program. It bears out Richard's results.
> 
> Indeed (I would expect nothing else).  But the result is dependent on
> the base so there is some ambiguity in the question.
> 
> Here is a Haskell program (well, some Haskell functions) that can give
> the answer for various bases:
> 
>   digits b n = if n == 0 then [] else r : digits b q
>     where (q, r) = divMod n b
>    
>   dSum b n = sum $ digits b n
>    
>   crossSum b n = head $ dropWhile (>= b) $ iterate (dSum b) n
> 
> *Main> let n = 58349863148967341986793418678943167894317568943579812347643263461438776834177468314765864533703574653715456716465804656089576907569568456680257542768434686845796847604780607596864802468874265807426587026578406466539046579467684906749046758049663588463065836688638658768635806365889683658746862486247487652774625076485806648907696785970467957869053868763688046236880752825686569877668097860897676807746897456368844688745768468242622686282862869874986865749685796854096857706759759674569074359357697539375903576096780074367589368590356896686539
> *Main> dSum 10 n
> 2977
> *Main> crossSum 10 n
> 7
> *Main> crossSum 2 n
> 1
> *Main> crossSum 5 n
> 3
> 

And a Python implementation:

>>> def cs(ys) :
...     return sum([int(x) for x in str(ys)])
>>> cs(xs)
2977
>>> cs(cs(xs))
25
>>> cs(cs(cs(xs)))
7

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Thread

C o m p e t i t i o n . I I <he12457@hotmail.com> - 2021-01-09 11:25 -0800
  Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-10 09:21 +0000
    Re: C o m p e t i t i o n . I I <he12457@hotmail.com> - 2021-01-10 12:01 -0800
      Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-10 22:15 +0000
        Re: C o m p e t i t i o n . I I <kpuctjanpobam@mail.com> - 2021-01-12 05:17 -0800
          Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-12 16:16 +0000
            Re: C o m p e t i t i o n . Y A <kpuctjanpobam@mail.com> - 2021-01-12 15:25 -0800
              Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-13 09:14 +0000
                Re: C o m p e t i t i o n . Y A <kpuctjanpobam@mail.com> - 2021-01-13 02:31 -0800
                Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-13 20:01 +0000
                Re: C o m p e t i t i o n . ند ارائه نماييدبا تشکر ند ارائه نمايي تش <kpuctjanpobam@mail.com> - 2021-01-14 08:29 -0800
                Re: C o m p e t i t i o n . ند ارائه نماييدبا تشکر ند ارائه نمايي تش <kpuctjanpobam@mail.com> - 2021-01-14 08:48 -0800
                Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-14 19:16 +0000
                Re: C o m p e t i t i o n . H e <he12457@hotmail.com> - 2021-01-14 11:28 -0800
                Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-15 07:46 +0000
                Re: C o m p e t i t i o n . Peter 'Shaggy' Haywood <phaywood@alphalink.com.au> - 2021-01-17 23:23 +1100
                Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-22 06:36 +0000
                Re: C o m p e t i t i o n . David Brown <david.brown@hesbynett.no> - 2021-01-15 11:13 +0100
                Re: C o m p e t i t i o n . Peter 'Shaggy' Haywood <phaywood@alphalink.com.au> - 2021-01-15 02:01 +1100
                Re: C o m p e t i t i o n . Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-01-15 00:23 +0000
                Re: C o m p e t i t i o n . David Brown <david.brown@hesbynett.no> - 2021-01-15 13:56 +0100
                Re: C o m p e t i t i o n . H e <he12457@hotmail.com> - 2021-01-17 03:23 -0800
                Re: C o m p e t i t i o n . Richard Heathfield <rjh@cpax.org.uk> - 2021-01-17 18:43 +0000

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