Re: Some Questions From Greece!!!

 James Kanze <>
Sun, 09 Sep 2007 20:13:05 -0000
On Sep 8, 2:28 pm, "osmium" <> wrote:

"ConX." writes:


1. We don't know which library is more commonly used by the world wide
programmers society. Our professor has tough us about stdio and some
other ways that he calls them "low level" (ex. read, open, _open etc)
which are difficult to use. But as we can see the most programmers use
Really what do you suggest us to learn?

As I read your post, you are enrolled in a course in C++, not C/C++. So
your first choice should be fstream. He is probably teaching the C way
because it is easier to learn. Real C++ programmers use fstream.

Not always. In fact, I find that fstream is fairly rare in my
code (and stdio, of course, completely absent), although
stringstream is fairly frequent. In modern programs, most IO
seems to be to systems not covered by the traditional stream IO:
data bases, sockets and GUIs. (The iostream's do get extended
to handle some of this, of course.)

2. Now as we are studying for the exams we are confused with binary
files. We are compiling some scripts and as we read the file we they
have created we see exactly the same result either we have set it in
text or binary mode.
How are we able to see that we achieved to create a binary file?

"Binary file" as used in C++ ( and inherited from C) is a very
bad choice of words.

IMHO, the problem isn't so much the word, as where it appears.
What is "binary" isn't the [io]stream (which is mainly concerned
with formatting), but the type of file. Apply it to filebuf
(the only class which actually uses it), and it fully makes

It involves different ways of encoding the '\n' character on the
storage medium.

Not only. Fundamentally, C++ (like C) deals with two types of
files: binary and text. On systems where there really is just
one type of file, like Windows or Unix, the differences are
restricted to how '\n' and EOF are encoded. On other systems,
binary and text may use different file types at the system level
(and it may not even be possible to open a file that was written
as binary in text mode, or vice versa).

There is a transparent (hidden) translation mechanism that
occurs on some systems. Notably Windows stores '\n' as
<LF><CR> (or the inverse, I can never recall which),
externally but obeys '\n' internally. This presumes the ASCII
character set.

I believe that some ports of C to IBM mainframes translated from
ASCII to EBCDIC in text mode: internally, C used ASCII (because
so many C programs assumed this), but externally, text files
were EBCDIC.

Browsing on google *groups* will yield an interminable set of
discussions on this subject.

Yes. But for most people, it's sufficient to say that if your
writing text to a local disk, to be read on the same (or a
similar) machine, then you should use text. In all other cases,
you probably want binary. And of course, if the format itself
isn't pure text, you probably don't want iostream at all.

James Kanze (GABI Software)
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