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Re: while loop condition doesn't work

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On 20/01/17 15:45, Alla _ wrote:
> On Friday, January 20, 2017 at 6:17:01 PM UTC+3, Ben Bacarisse wrote:
>> Alla _ <modelling.data@gmail.com> writes:
<snip>
>>>         while(not_converted > ptr && !isspace(*not_converted))
>>
>> Why are you interested in non-spaces? [...]
> With this function I just need two numbers out of 5 - the first and the last
> one. At the moment the function is called the input
> contains numbers, separated by commas (csv format), as in
> 1062,1252,1587,1934,2519

In which case you have no need to call isspace at all, and the whole 
thing can be done in less than a dozen lines of very simple code.

n = 0; /* this is how many numbers you've successfully parsed */
do
{
   /* try to convert a number */
   num[n] = strtod(ptr, &not_converted, 10);

   /* if that worked... */
   if(not_converted > ptr)
   {
     /* record the success */
     ++n;

     /* if we're just at a field boundary, we
        want to move to just past that boundary.
        If we're at the end of the string,
        then two things happen: (1) we can't be
        sure that it's legal to move past the '\0'
        AND (2) there is in any case nothing more
        to convert.

        So if we're not at '\0', we want ptr to
        point to not_converted + 1. Otherwise, we
        want ptr to point to not_converted (which will
        terminate the loop).

        In C, the result of a condition is either 0
        (false), or 1 (true), and this happens to map
        precisely onto what we want. So we can do this:
      */

     ptr = not_converted + (*not_converted != '\0');
   }
} while(not_converted > ptr && n < expected_count);

expected_count would appear to be 5 in this case. If it's always 5, use 
a constant e.g. #define NUMBERS_PER_LINE 5

if(n == expected_count) you have all the numbers you need. If it isn't, 
you don't, and presumably that's an error.

Note the complete absence of isspace.

-- 
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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while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 01:24 -0800
  Re: while loop condition doesn't work mark.bluemel@gmail.com - 2017-01-20 03:29 -0800
  Re: while loop condition doesn't work Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-20 12:19 +0000
    Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 05:12 -0800
      Re: while loop condition doesn't work Richard Heathfield <rjh@cpax.org.uk> - 2017-01-20 13:17 +0000
        Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 05:20 -0800
        Re: while loop condition doesn't work Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-20 15:07 +0000
    Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 05:31 -0800
      Re: while loop condition doesn't work Manfred <noname@invalid.add> - 2017-01-20 15:23 +0100
      Re: while loop condition doesn't work Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-20 15:16 +0000
        Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 07:45 -0800
          Re: while loop condition doesn't work Richard Heathfield <rjh@cpax.org.uk> - 2017-01-20 16:06 +0000
            Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 08:37 -0800
            Re: while loop condition doesn't work David Brown <david.brown@hesbynett.no> - 2017-01-20 17:54 +0100
              Re: while loop condition doesn't work Richard Heathfield <rjh@cpax.org.uk> - 2017-01-20 17:04 +0000
                Re: while loop condition doesn't work David Brown <david.brown@hesbynett.no> - 2017-01-20 19:08 +0100
                Re: while loop condition doesn't work Tim Rentsch <txr@alumni.caltech.edu> - 2017-01-30 12:51 -0800
                Re: while loop condition doesn't work Keith Thompson <kst-u@mib.org> - 2017-01-30 14:09 -0800
                Re: while loop condition doesn't work supercat@casperkitty.com - 2017-01-30 14:57 -0800
                Re: while loop condition doesn't work Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-01 21:31 -0800
                Re: while loop condition doesn't work Keith Thompson <kst-u@mib.org> - 2017-02-02 10:01 -0800
                Re: while loop condition doesn't work Tim Rentsch <txr@alumni.caltech.edu> - 2017-02-04 00:22 -0800
              Re: while loop condition doesn't work Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-20 19:12 +0000
                Re: while loop condition doesn't work Richard Heathfield <rjh@cpax.org.uk> - 2017-01-23 10:54 +0000
            Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 23:22 -0800
              Re: while loop condition doesn't work Richard Heathfield <rjh@cpax.org.uk> - 2017-01-23 11:02 +0000
            Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-21 01:22 -0800
              Re: while loop condition doesn't work Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-21 11:00 +0000
                Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-21 08:35 -0800
                Re: while loop condition doesn't work Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-21 17:17 +0000
                Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-21 09:32 -0800
          Re: while loop condition doesn't work Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-20 19:16 +0000
            Re: while loop condition doesn't work Richard Heathfield <rjh@cpax.org.uk> - 2017-01-23 11:03 +0000
    Re: while loop condition doesn't work David Brown <david.brown@hesbynett.no> - 2017-01-20 14:34 +0100
      Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 07:40 -0800
        Re: while loop condition doesn't work Richard Heathfield <rjh@cpax.org.uk> - 2017-01-20 15:47 +0000
          Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 08:26 -0800
            Re: while loop condition doesn't work David Brown <david.brown@hesbynett.no> - 2017-01-20 18:01 +0100
              Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 09:26 -0800
                Re: while loop condition doesn't work David Brown <david.brown@hesbynett.no> - 2017-01-20 19:02 +0100
                Re: while loop condition doesn't work Alla _ <modelling.data@gmail.com> - 2017-01-20 10:13 -0800
                Re: while loop condition doesn't work Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-21 05:36 -0800

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