Clarification regarding #include declarations.

[Rakesh]

Hi,
I was writing this C++ program wherein I used an include statement
like -
#include <iostream.h>

I was told by my co-worker that this form of including a file is
deprecated and should not be used, instead it ought to be something
like

#include <iostream>

And this ought to be the standard way of including files.
So does this imply that , my program should not have any header files
of the following type , something like -
#include <myclassdef.h>

...

is that deprecated / alternate syntax of #include that achieves the
same thing.

- Rakesh

[Rob Williscroft]

Rakesh wrote in news:3e**************************@posting.google.c om in
comp.lang.c++:

Hi,
I was writing this C++ program wherein I used an include statement
like -
#include <iostream.h>

I was told by my co-worker that this form of including a file is
deprecated and should not be used, instead it ought to be something
like
Its not deprecated, deprecated means something that was/is standard
that will nolonger be standard at some point in the future.

There never was a *standard* header <iostream.h>.

#include <iostream>
This is part of the standard library, and is what you should use.

And this ought to be the standard way of including files.
So does this imply that , my program should not have any header files
of the following type , something like -
#include <myclassdef.h>

No, this should be:

#include "myclassdef.h"

Only use the <> syntax for header's that come with your implementation
(aka compiler), including the headers that are part of the Standard
library.

Also, what file extension you give *your* files is up to you, .h, .hpp
and .hxx are common. Some OS's allow your files to be assosiated with
a particular application based on the files extension (an editor say)
so you should probably use one if these.
...

is that deprecated / alternate syntax of #include that achieves the
same thing.

The headers <stdio.h> etc, inhereted from C are *deprecated*, you should
use <cstdio> etc, instead, which only supply the standard library in
namespace std:

Depricate this:

#include <stdio.h>
int main()
{
printf( "Helow world\n" );
}

Code like this:

#include <cstdio>
int main()
{
std::printf( "Helow world\n" );
}

HTH.

Rob.
--
http://www.victim-prime.dsl.pipex.com/

[Kevin Goodsell]

Rob Williscroft wrote:

Depricate this:

#include <stdio.h>
int main()
{
printf( "Helow world\n" );
}

Code like this:

#include <cstdio>
int main()
{
std::printf( "Helow world\n" );
}

Personally I'd deprecate any use of printf/scanf-related functions.

-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.

[Rob Williscroft]

Kevin Goodsell wrote in news:v_zgc.19887$A_4.14887
@newsread1.news.pas.earthlink.net in comp.lang.c++:

Rob Williscroft wrote:

Depricate this:

#include <stdio.h>
int main()
{
printf( "Helow world\n" );
}

Code like this:

#include <cstdio>
int main()
{
std::printf( "Helow world\n" );
}

Personally I'd deprecate any use of printf/scanf-related functions.

Well I've never used scanf, so I really don't care,
remove it, depricate it, enhance it, I'll never notice :).

printf can be safe, gcc has been doing this for years and I
got the impression from a recient comp.lang.c x-post that
many in the C world consider this to be something that
should be expected from a a High Quality(tm) implementation.

In the next standard we may get templates function's with
an unlimited number of arguments (an equivalent of , ...),
so we may be able to fix the "type saftey" problem with
std::printf().

Even better we can write:

template < typename T, template Args ... >
std::shared_ptr< T > std::shared_new( Args );

template < typename T, template Args ... >
std::auto_ptr< T > std::auto_new( Args );

and can depricate new and delete :). (*)

Rob.
--
*) Only /half/ joking.

[Kevin Goodsell]

Rob Williscroft wrote:

printf can be safe, gcc has been doing this for years and I
got the impression from a recient comp.lang.c x-post that
many in the C world consider this to be something that
should be expected from a a High Quality(tm) implementation.
GCC's printf() (and scanf()) format checking is cool, but it's not a
general solution. It can't possibly check all formats, because formats
are not necessarily known at compile time. We don't see a lot of
run-time generated format strings, but it's the only way to do some
things (unless you drop printf()/scanf() completely and roll your own,
which isn't necessarily a bad idea). The obvious example, I think, is a
%s or %[ scanf() format where the corresponding char array argument is
dynamically allocated, or of unknown (at compile-time) size for other
reasons, such as being the argument to a function.

I can't think of an obvious printf() example -- field widths can be
specified with a variable in printf() -- so maybe the situation isn't as
bad there. Of course, even if it's not *necessary* to use dynamic format
strings for a particular situation, that doesn't mean somebody won't use
them.

In the next standard we may get templates function's with
an unlimited number of arguments (an equivalent of , ...),
so we may be able to fix the "type saftey" problem with
std::printf().

Overloading + chaining (overloading being the key part, chaining is just
for convenience), like in the standard streams, seems like the "right"
solution to me. I don't know about this.

-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.

[Rakesh]

Kevin Goodsell <us*********************@neverbox.com> wrote in message > >

Code like this:

#include <cstdio>
int main()
{
std::printf( "Helow world\n" );
}

Thanks for letting me know a different syntax.
Personally I'd deprecate any use of printf/scanf-related functions.

I am a little bit confused here. You mean to say, they are not
supposed to be used ( is it that we should use only - cin , cout or
something similar to that).

- Rakesh.

[Rakesh]

Rob Williscroft <rt*@freenet.co.uk> wrote in message news:<Xn**********************************@130.133 .1.4>...

Depricate this:

#include <stdio.h>
int main()
{
printf( "Helow world\n" );
}

Code like this:

#include <cstdio>
int main()
{
std::printf( "Helow world\n" );
}

Thanks for letting me know that, Rob.

- Rakesh.

[Kevin Goodsell]

Rakesh wrote:

Kevin Goodsell <us*********************@neverbox.com> wrote in message > >

Personally I'd deprecate any use of printf/scanf-related functions.

I am a little bit confused here. You mean to say, they are not
supposed to be used ( is it that we should use only - cin , cout or
something similar to that).

I'm saying that I would recommend not using them. They are very
difficult to use correctly, and your compiler probably won't tell you
when you use them wrong.

Anything that defeats type-checking is best avoided, particularly when
better options are available (such as standard streams classes).

-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.