Subj : Re: fstream arrays
To   : borland.public.cpp.borlandcpp
From : "D Kat" <disisdkat@hotmail.com>
Date : Wed Mar 10 2004 12:43 pm

You cannot have an array of 1 (ofstream outfiles[1] is illegal) ... I do
absolutely noting different in the code other than if I am running an
experiment that only uses 1 Subject (or there is only one data file that is
saved) then I define outfiles to not be an array where in experiments in
which I run more than one subject (having more than one data file that needs
to be saved) I define the ofstream as an array.  The multiple opening of
files is put in a simple for loop - for ( sub = 0 ; sub < MAXSUB ; sub ++)
.... same code but out_files is now out_files[sub].  This is what I find
baffling.  The code is the same except for the issue of it being an array
item.  In trying to debug I have eliminated the loop and used the exact same
code as with a single subject but replaced
ofstream outfiles with ofstream outfiles[2]
and
out_files with out_files[0];
The first gives not error the second does.


"Thomas Maeder [TeamB]" <maeder@glue.ch> wrote in message
news:m2d682x0xw.fsf@madbox2.local...
> "D Kat" <disisdkat@hotmail.com> writes:
>
> > The error (and I have stepped through this as well) is done within the
> > function get_subj_fp - I have taken out the error check on the return of
the
> > function because it doesn't matter - what I'm saying is ignore the fact
that
> > I don't care if I get an error or not.  That is not the point.  In my
way of
> > veiwing the world Arrays are pointers.
>
> You should change your view then. Arrays and pointers are totally
different
> things. The only thing that relates them to each other is that an array
> is implicitly converted into a pointer to its first element when
necessary.
>
>
> > That is how I refer to them.  This
> > is what I care about
> >
> > if(!out_files[i]) ...... tests as 1 or as an ERROR
> > if(!out_file).... tests as 0 or NOT ERROR.
> >
> > ofstream outfiles;
> > vs
> > ofstream outfiles[3];
> >
> > Why does one return false while the other doesn't  -  BOTH successfully
> > open, write and save.
>
> There is no conceptual difference between an ofstream that is an array
> element and an ofstream that isn't. You seem to do something differently
> when dealing with the array.
>
>
> Consider starting with a simple ofstream. Then change it into an array of
> 1 (one) ofstream; simply add [1] in its definition and [0] wherever you
> use it. Then replace the [1] by a [nrOfStreams] (with nrOfStreams being
> a constent unsigned int of value 1) and the [0] by loops from 0 to
> nrOfStreams (not inclusive). Then increase nrOfStreams to the value you
> need it to have.

.