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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: while loop vs do while loop reading from the file issue
Date: Wed, 07 Dec 2016 11:50:48 -0800
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Barry Schwarz <schwarzb@dqel.com> writes:
[...]
> Example 1:  Place the call to fscanf inside an if statement:
>       if (fscanf( cfPtr, "%d%29s%lf", &account, name, &balance ) > 0)
> Now the following call to printf will not execute if fscanf fails.

I'd write "== 3" rather than "> 0".  fscanf() could return 1 or 2 if
it's able to read only 1 or 2 items rather than the requested 3.  You
might want to treat reading 1 or 2 items differently from other kinds of
failure, but for a small demo program like this it's probably best to
treat anything other than 3 as an error.

>>            fscanf( cfPtr, "%d%29s%lf", &account, name, &balance );
>
> Example 2:  Insert an feof test just prior to the call to printf:
>      if (!feof( cfPtr ))
> Same effect as above.

Not quite.  feof() will return false (0) if no more input is available
due to an I/O error; in that case ferror() will return true.

[...]

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"