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Re: Beginner....Decimal/Octal converter help

From Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups comp.lang.c
Subject Re: Beginner....Decimal/Octal converter help
Date 2022-09-10 19:03 +0100
Organization A noiseless patient Spider
Message-ID <87zgf714zc.fsf@bsb.me.uk> (permalink)
References (1 earlier) <86leqsr091.fsf@linuxsc.com> <S8MSK.400474$iiS8.244727@fx17.iad> <tfhn50$1c35d$1@dont-email.me> <875yhv30nu.fsf@bsb.me.uk> <tfi6jk$1f9ct$1@dont-email.me>

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David Brown <david.brown@hesbynett.no> writes:

> On 10/09/2022 13:54, Ben Bacarisse wrote:
>> David Brown <david.brown@hesbynett.no> writes:
>> 
>>> On 09/09/2022 21:06, Scott Lurndal wrote:
>>>> Tim Rentsch <tr.17687@z991.linuxsc.com> writes:
>>>>> ManyBeers <markzuffi@yahoo.com> writes:
>>>>>
>>>>>> Hello I am teaching myself C and I need some help with a problem.
>>>>>> After a search for dec/oct convert I found this code:
>>>>>>
>>>>>> [..code..]
>>>>>
>>>>> I would like to offer a different kind of answer to your
>>>>> questions.  First a suggestion:  for this kind of problem I think
>>>>> you will find it helpful to use unsigned types exclusively.  In
>>>>> the code below we will need (besides a plain 'unsigned' here and
>>>>> there) two types, one for 8-bit values and one for 32-bit values:
>>>>>
>>>>>    typedef unsigned char  UC;
>>>>>    typedef unsigned int   UI;
>>>> There already standard perfectly cromulent typedefs for both,
>>>> uint8_t and uint32_t.
>>>
>>> And those type names are better in a number of ways.  They are
>>> clearer, more precise, and hide the design flaw in C of mixing the
>>> concepts of "character" and "small number".  In particular, they
>>> specify exactly what size your numbers are, rather that having hidden
>>> assumptions in the code.
>> But they both say too much.  The 'source' integer size need not be 32
>> bits and, given that there are no other obvious requirements, unsigned
>> int seems to me to be the natural choice.  And if the requirements were
>> that 32-bit numbers could be handled, uint_least32_t (or uint_fast32_t)
>> more precisely meets the need.
>
> "unsigned int" might have been a reasonable choice, but Tim's code
> goes on to rely on it being 32-bit.  (Or to be more accurate, it
> /says/ it relies on it being 32-bit.)
>
>> And the uint8_t is also unnecessarily specific.  We do want to know that
>> digits up to 255 can be stored, but nothing goes wrong if the type is
>> wider.  uint_least8_t says exactly what's wanted and no more.
>> Mind you, since char is guaranteed to be at least 8 bits wide, unsigned
>> char is effectively uint_least8_t.
>> 
>
> There is such a thing as being /too/ portable.

I was not talking about portability.  It's handy when types say what's
needed and what isn't.  uint8_t says too much.  uint_least8_t is better
because it says exactly what's needed and what isn't.  The suggestion
had nothing to do with portability.

> There are some real-world C implementations that do not have uint8_t
> and/or uint32_t, but the overlap in code between these niche systems
> and "normal" systems is almost non-existent.  So the use of
> "uint_least8_t", "uint_fast32_t" and similar types is IMHO needless
> complication and verbosity, and certainly not something beginners
> should need to bother about.

Really?  That's a complication?

Being a beginners is another matter.  We don't know what sort of
beginner this is (I think it was a drive-by anyway), but none of the
types is ideal for a beginner.  In fact, I imagine that's partly what
motivated TR's choice.

> You are, of course, technically correct
> in everything you write here - but that still does not make these
> types a better choice in the circumstances.  (Again, all in my humble
> opinion.)
>
> An alternative approach would be to have typedefs that are descriptive
> and application-specific, and which can be changed later to allow
> different sizes to be converted.  Especially in light of it being code
> for someone relatively unfamiliar with the language, I'd err on the
> side of longer names (and certainly not cryptic short abbreviations
> that are not particularly relevant to the usage) :
>
> 	typedef uint8_t digit_type;
> 	typedef uint32_t number_type;

But then why not use the more accurate last8 (and least32) types?  They
"complicate" just two lines of code and the verbosity criticism
vanishes.

-- 
Ben.

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Thread

Beginner....Decimal/Octal converter help ManyBeers <markzuffi@yahoo.com> - 2022-09-08 11:34 -0700
  Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-08 11:56 -0700
  Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-08 20:19 +0100
  Re: Beginner....Decimal/Octal converter help Barry Schwarz <schwarzb@delq.com> - 2022-09-08 12:34 -0700
  Re: Beginner....Decimal/Octal converter help Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2022-09-08 20:38 -0600
  Re: Beginner....Decimal/Octal converter help Öö Tiib <ootiib@hot.ee> - 2022-09-09 03:22 -0700
    Re: Beginner....Decimal/Octal converter help gazelle@shell.xmission.com (Kenny McCormack) - 2022-09-09 13:30 +0000
  Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-09 09:16 -0700
    Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-09 19:06 +0000
      Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-10 11:58 +0200
        Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-10 11:37 +0100
          Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-10 13:05 +0200
          Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-10 14:42 +0000
            Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-10 16:10 +0100
              Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-10 18:14 +0200
        Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-10 12:54 +0100
          Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-10 16:22 +0200
            Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-10 19:03 +0100
              Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-10 19:30 +0100
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-10 19:47 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-11 14:07 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-11 16:12 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-11 17:58 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-11 21:14 +0100
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 20:01 -0700
                Re: Beginner....Decimal/Octal converter help Richard Damon <Richard@Damon-Family.org> - 2022-09-11 23:32 -0400
                Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-12 13:52 +0000
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-14 03:24 -0700
                Re: Beginner....Decimal/Octal converter help Richard Damon <Richard@Damon-Family.org> - 2022-09-14 08:10 -0400
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-12-26 06:09 -0800
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-12 16:53 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-12 16:48 +0100
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-12 17:46 +0100
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-12 20:37 +0100
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 00:03 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-13 12:31 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-13 12:48 +0100
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 14:18 +0100
                Re: Beginner....Decimal/Octal converter help Anton Shepelev <anton.txt@g{oogle}mail.com> - 2022-09-13 17:13 +0300
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-13 16:50 +0100
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 18:47 +0100
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 03:16 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-13 20:15 +0200
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-13 20:29 +0000
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 22:22 +0100
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-13 14:37 -0700
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-13 23:16 +0100
                Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-13 22:16 +0000
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-13 16:15 -0700
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-13 16:15 -0700
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-14 10:58 +0100
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 15:36 +0100
                Re: Beginner....Decimal/Octal converter help Richard Harnden <richard.nospam@gmail.com> - 2022-09-14 21:53 +0100
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-14 05:55 +0000
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 10:10 +0200
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-14 07:54 -0700
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 18:32 +0200
                Re: Beginner....Decimal/Octal converter help Bart <bc@freeuk.com> - 2022-09-14 18:39 +0100
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-15 01:12 +0000
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-15 09:11 +0200
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-15 08:07 -0700
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-14 18:40 +0000
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-14 05:45 +0000
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 12:11 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 09:57 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 03:09 +0100
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 10:29 +0200
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-14 15:14 +0100
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-14 07:36 -0700
                Re: Beginner....Decimal/Octal converter help Öö Tiib <ootiib@hot.ee> - 2022-10-03 01:10 -0700
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-03 11:36 +0100
                Re: Beginner....Decimal/Octal converter help Öö Tiib <ootiib@hot.ee> - 2022-10-04 02:13 -0700
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-04 16:27 +0100
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-13 11:48 -0700
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-14 10:38 +0200
                Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-14 14:27 +0000
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-14 07:58 -0700
                Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-16 13:06 -0700
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-16 13:16 -0700
                Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-12 17:55 +0000
                Re: Beginner....Decimal/Octal converter help Kaz Kylheku <480-992-1380@kylheku.com> - 2022-09-12 18:22 +0000
                Re: Beginner....Decimal/Octal converter help Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-09-12 20:41 +0100
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-11 15:45 -0700
                Re: Beginner....Decimal/Octal converter help Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-09-11 15:41 -0700
                Re: Beginner....Decimal/Octal converter help David Brown <david.brown@hesbynett.no> - 2022-09-12 17:06 +0200
              Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 06:46 -0700
          Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 06:57 -0700
      Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 07:07 -0700
        Neologism (Was: Beginner....Decimal/Octal converter help) gazelle@shell.xmission.com (Kenny McCormack) - 2022-09-11 14:18 +0000
        Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-11 16:33 +0000
          Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-13 15:40 -0700
  Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-09 23:08 +0000
    Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-11 06:37 -0700
      Re: Beginner....Decimal/Octal converter help scott@slp53.sl.home (Scott Lurndal) - 2022-09-11 16:31 +0000
        Re: Beginner....Decimal/Octal converter help Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-09-13 15:44 -0700

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