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Re: Optimizing the code: way to reduce if, else if-s within the loop?

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On Sunday, January 22, 2017 at 7:55:02 PM UTC+3, James R. Kuyper wrote:
> On 01/22/2017 11:16 AM, Alla _ wrote:
> > On Sunday, January 22, 2017 at 6:47:47 PM UTC+3, Barry Schwarz wrote:
> >> On Sun, 22 Jan 2017 03:24:39 -0800 (PST), Alla _
> >> <modelling.data@gmail.com> wrote:
> >>
> >>>  *((char*)dat_years + offset) = strtod(ptr, &not_converted);
> >>
> >> Here is the line of code I suggested
> >>      *(double*)((char*)dat_years + offset) = strtod(...);
> >>
> >> You chose to leave out a significant piece, apparently thinking it
> >> didn't matter.
> > Now it's my time to grumble )))) I didn't leave out that "significant piece,
> > apparently (I wish you didn't use this word - it did make things worse)
> > thinking it didn't matter" = wrong. ...
> 
> > ... I have mentioned *why*
> > it is not in my code. ...
> 
> I believe you're referring to the comment: "Also (double) cast
> is not allowed by compiler because struct members all have
> double type." The type of the members is completely irrelevant to the 
> validity of that cast, because there is no use of any of those members 
> anywhere near the cast. Note also that it's a (double*) cast, not a 
> (double) cast. If you miscopied Barry's code as follows:
> 
>      *(double)((char*)dat_years + offset) = strtod(...);
> 
> then the compiler should complain about the fact that you're trying to 
> convert a char* value to a double, and then trying to apply the unary * 
> operator to a value of type double. However, that's not because of any 
> problem with members having double type.

Yes, that's exactly what happened. I can't find any plausible reason
why I made that typo - I was absolutely sure I use (double*), and therefore
before coming here I spent over 2,5 hours searching the net for 
possible reasons and reading different material, rewriting the code, and 
not understanding what could go wrong. 
Apologies! I have heard that even professionals can miss these sort of typos;
though this doesn't justify my mistake at all. 

> 
> > ... I usually don't highlight things, because it is
> > a rather bad manner, but sometimes even I get tired of groundless
> > accusations - my compiler didn't allow me to use double casting
> 
> Any compiler which objects to the correct version of the code that Barry 
> provided is not a conforming implementation of C. I strongly suspect 
> that what it objected to is something significantly different from 
> Barry's code. If you could, would you provide the exact text of a 
> minimal program containing only that code, and just enough other code to 
> define the things used in that code, and the error messages you get when 
> you compile it?
> 
> > because all values already are of double type.
> 
> All values? None of the following values has double type:
>      dat_years			data*
>      (char*)dat_years		char*
>      offset			int
>      (char*)dat_year+offset	char*
>      *((char*)dat_year+offset)	char
> 
> The most important case is that last one - the fact that it does not 
> have double type is the reason your code is wrong, and is also the 
> reason why Barry's code contains the cast to (double*).

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Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-21 08:52 -0800
  Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-21 09:35 -0800
  Re: Optimizing the code: way to reduce if, else if-s within the loop? Barry Schwarz <schwarzb@dqel.com> - 2017-01-21 10:28 -0800
    Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-21 23:49 -0800
    Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 00:29 -0800
      Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-22 10:54 +0000
        Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 03:28 -0800
          Re: Optimizing the code: way to reduce if, else if-s within the loop? Keith Thompson <kst-u@mib.org> - 2017-01-22 07:44 -0800
            Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 08:24 -0800
            Re: Optimizing the code: way to reduce if, else if-s within the loop? Barry Schwarz <schwarzb@dqel.com> - 2017-01-22 10:43 -0800
              Re: Optimizing the code: way to reduce if, else if-s within the loop? Keith Thompson <kst-u@mib.org> - 2017-01-22 12:22 -0800
        Re: Optimizing the code: way to reduce if, else if-s within the loop? BartC <bc@freeuk.com> - 2017-01-22 11:33 +0000
          Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-22 13:23 +0000
            Re: Optimizing the code: way to reduce if, else if-s within the loop? BartC <bc@freeuk.com> - 2017-01-22 13:28 +0000
              Re: Optimizing the code: way to reduce if, else if-s within the loop? Keith Thompson <kst-u@mib.org> - 2017-01-22 07:47 -0800
                Re: Optimizing the code: way to reduce if, else if-s within the loop? BartC <bc@freeuk.com> - 2017-01-22 16:00 +0000
                Re: Optimizing the code: way to reduce if, else if-s within the loop? David Brown <david.brown@hesbynett.no> - 2017-01-22 18:23 +0100
                Re: Optimizing the code: way to reduce if, else if-s within the loop? "James R. Kuyper" <jameskuyper@verizon.net> - 2017-01-22 13:47 -0500
                Re: Optimizing the code: way to reduce if, else if-s within the loop? Barry Schwarz <schwarzb@dqel.com> - 2017-01-22 10:43 -0800
                Re: Optimizing the code: way to reduce if, else if-s within the loop? "James R. Kuyper" <jameskuyper@verizon.net> - 2017-01-22 13:53 -0500
                Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-22 18:57 +0000
                Re: Optimizing the code: way to reduce if, else if-s within the loop? BartC <bc@freeuk.com> - 2017-01-22 19:18 +0000
                Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-22 21:54 +0000
        Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-23 02:41 -0800
          Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-23 11:20 +0000
            Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-23 03:53 -0800
              Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-23 12:12 +0000
    Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 03:24 -0800
      Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-22 13:16 +0000
      Re: Optimizing the code: way to reduce if, else if-s within the loop? Barry Schwarz <schwarzb@dqel.com> - 2017-01-22 07:47 -0800
        Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 08:16 -0800
          Re: Optimizing the code: way to reduce if, else if-s within the loop? "James R. Kuyper" <jameskuyper@verizon.net> - 2017-01-22 11:54 -0500
            Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 11:23 -0800
          Re: Optimizing the code: way to reduce if, else if-s within the loop? Barry Schwarz <schwarzb@dqel.com> - 2017-01-22 11:08 -0800
            Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 22:19 -0800
            Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 22:41 -0800
              Re: Optimizing the code: way to reduce if, else if-s within the loop? Robert Wessel <robertwessel2@yahoo.com> - 2017-01-23 02:17 -0600
              Re: Optimizing the code: way to reduce if, else if-s within the loop? Barry Schwarz <schwarzb@dqel.com> - 2017-01-23 02:16 -0800
                Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-23 03:59 -0800
              Re: Optimizing the code: way to reduce if, else if-s within the loop? Keith Thompson <kst-u@mib.org> - 2017-01-23 08:44 -0800
        Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 08:23 -0800
      Re: Optimizing the code: way to reduce if, else if-s within the loop? Barry Schwarz <schwarzb@dqel.com> - 2017-01-22 07:52 -0800
        Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-22 08:17 -0800
    Re: Optimizing the code: way to reduce if, else if-s within the loop? Richard Heathfield <rjh@cpax.org.uk> - 2017-01-23 17:11 +0000
      Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-23 10:35 -0800
        Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-23 10:38 -0800
        Re: Optimizing the code: way to reduce if, else if-s within the loop? BartC <bc@freeuk.com> - 2017-01-23 19:06 +0000
        Re: Optimizing the code: way to reduce if, else if-s within the loop? Barry Schwarz <schwarzb@dqel.com> - 2017-01-23 14:31 -0800
          Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-23 21:31 -0800
          Re: Optimizing the code: way to reduce if, else if-s within the loop? Alla _ <modelling.data@gmail.com> - 2017-01-24 01:56 -0800
            Re: Optimizing the code: way to reduce if, else if-s within the loop? Manfred <noname@invalid.add> - 2017-01-24 14:38 +0100
            Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-24 13:57 +0000
  Re: Optimizing the code: way to reduce if, else if-s within the loop? BartC <bc@freeuk.com> - 2017-01-23 12:38 +0000
    Re: Optimizing the code: way to reduce if, else if-s within the loop? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-23 15:08 +0000
  Re: Optimizing the code: way to reduce if, else if-s within the loop? m.labanowicz@gmail.com - 2017-01-23 07:08 -0800

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