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Re: newby question on C I/O

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On 11/21/2011 02:39 AM, David Thompson wrote:
> On Fri, 04 Nov 2011 21:46:03 -0400, James Kuyper
> <jameskuyper@verizon.net> wrote:
> 
>> On 11/04/2011 06:07 PM, analyst41@hotmail.com wrote:
>>> I have a file that looks like
>>>
>>> Value Cost Special_Status
>>> 12    34          Yes
>>> 21    44          yes
>>> 32    43           no
>>> .....................
>>>
>>> I can read it into some arrays (or a data frame using R) using Fortran
> <snip>
>>>        read (1,*,end=100) values(j),costs(j),statuses(j)
>>
>> The '*' in that READ statement, where a FORMAT would ordinarily go,
>> indicates implicit formatting. A key difference between C and Fortran is
> 
> Yes. Formally called 'list-directed' formatting.
> 
>> that I/O is a built-in part of the Fortran language, while in C I/O is
>> handled by standard library functions. Given the way C functions work,
>> that means that something equivalent to the implicit formatting used by
>> the READ statement above isn't feasible in C. The simplest approach
> 
> Well, the syntax is a little different, but so is C stdio vs Fortran
> classic explicit-format. Functionally, what Fortran list-directed
> input does is a little different from what Standard C *scanf does, so
> you would have to write maybe a page or two of code to fullly handle
> it, which you could put in a utility function and reuse as needed. 

The key characteristic of Fortran list-directed input that I was talking
about is the fact that you don't have to identify the types of the
expressions you are printing; that information is implicitly determined
by looking at the expressions themselves. C++ function overloading makes
it feasible to do something similar in the <iostream> part of the C++
standard library (though you do have to provide your own overloads for
operator<<() and operator>>() for any user-defined type), but I don't
see any way to implement such a feature in "a page or two of code" in C.
Could you explain how that would work?

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newby question on C I/O "analyst41@hotmail.com" <analyst41@hotmail.com> - 2011-11-04 15:07 -0700
  Re: newby question on C I/O Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-04 20:50 -0400
    Re: newby question on C I/O "analyst41@hotmail.com" <analyst41@hotmail.com> - 2011-11-04 18:57 -0700
    Re: newby question on C I/O "analyst41@hotmail.com" <analyst41@hotmail.com> - 2011-11-07 17:10 -0800
      Re: newby question on C I/O Ian Collins <ian-news@hotmail.com> - 2011-11-08 14:47 +1300
      Re: newby question on C I/O "BartC" <bc@freeuk.com> - 2011-11-08 01:52 +0000
      Re: newby question on C I/O Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-07 20:56 -0500
        Re: newby question on C I/O Edward Rutherford <edward.p.rutherford79@REMOVETHIS.gmail.com> - 2011-11-08 20:27 +0000
          Re: newby question on C I/O Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-08 20:48 -0500
          Re: newby question on C I/O "BartC" <bc@freeuk.com> - 2011-11-09 11:12 +0000
            Re: newby question on C I/O James Kuyper <jameskuyper@verizon.net> - 2011-11-09 07:02 -0500
              Re: newby question on C I/O Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-11-09 16:12 +0000
        Re: newby question on C I/O - SUCCESS "analyst41@hotmail.com" <analyst41@hotmail.com> - 2011-11-08 16:12 -0800
  Re: newby question on C I/O James Kuyper <jameskuyper@verizon.net> - 2011-11-04 21:46 -0400
    Re: newby question on C I/O Ike Naar <ike@iceland.freeshell.org> - 2011-11-05 06:52 +0000
      Re: newby question on C I/O Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-05 04:13 -0700
      Re: newby question on C I/O James Kuyper <jameskuyper@verizon.net> - 2011-11-05 08:16 -0400
        Re: newby question on C I/O Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-05 09:21 -0400
      Re: newby question on C I/O Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-05 09:13 -0400
    Re: newby question on C I/O David Thompson <dave.thompson2@verizon.net> - 2011-11-21 02:39 -0500
      Re: newby question on C I/O James Kuyper <jameskuyper@verizon.net> - 2011-11-21 10:05 -0500
        Re: newby question on C I/O David Thompson <dave.thompson2@verizon.net> - 2012-01-19 02:40 -0500
  Re: newby question on C I/O "BartC" <bc@freeuk.com> - 2011-11-06 21:23 +0000
  Re: newby question on C I/O "analyst41@hotmail.com" <analyst41@hotmail.com> - 2011-11-10 18:00 -0800
    Re: newby question on C I/O Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-11 01:35 -0800
      Re: newby question on C I/O gazelle@shell.xmission.com (Kenny McCormack) - 2011-11-11 11:26 +0000
        Re: newby question on C I/O Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-11 04:41 -0800
          Re: newby question on C I/O gazelle@shell.xmission.com (Kenny McCormack) - 2011-11-11 14:14 +0000
            Re: newby question on C I/O Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-11-11 07:02 -0800
              Re: newby question on C I/O gazelle@shell.xmission.com (Kenny McCormack) - 2011-11-11 15:44 +0000

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