Making C better (by borrowing from C++)

[masood.iqbal]

I know that this topic may inflame the "C language Taleban", but is
there any prospect of some of the neat features of C++ getting
incorporated in C? No I am not talking out the OO stuff. I am talking
about the non-OO stuff, that seems to be handled much more elegantly in
C++, as compared to C. For example new & delete, references, consts,
declaring variables just before use etc.

I am asking this question with a vested interest. I would really like
to use these features in my C programs.

Masood

[websnarf]

Chris Croughton wrote:

On 12 Feb 2005 19:13:45 -0800, websnarf wrote:

C has const. I don't quite see how C++'s consts are not redundant
with either #define or enums. You can even make enums locally
scoped.

Try declaring an enum with floating point type. Or using a const
int as a case value. I think that C++ should have found something
else to call them (and both C and C++ should have stopped the
overloading of the 'static' keyword, C++ even adds yet another
meaning to it), but typed constants are useful and don't have the
pitfalls of macros.

Ok, I see -- you really want are read-only variables. Fair enough.

declaring variables just before use etc.

This is in C99, and personally I would rather have seen this
*REMOVED* from C++, than added to C. It makes the job of reading
code twice as hard -- if we wanted that, we might as well be using
Perl. If you want to do "just in time constructors", wrap your
code with additional scope.

Used properly (as in declaring loop variables only when they are
used) it makes it more readable, not less. I've seen a lot of
errors where someone has used a variable (often i or j) for a loop,
it has compiled (it was already declared) but it has done unexpected
things because it wasn't obvious that the variable was already in
use.

Ok, so then that's just it, then isn't it? Using it "properly" as you
say boils down to declarations of variables in the first expression of
a control statement such as for, while, if, or switch. Fine, but
that's a narrower extension than C++'s scheme.

At least my namespace extension remains intact. :)

---
Paul Hsieh
http://www.pobox.com/~qed/
http://bstring.sf.net/

[jacob navia]

Randy Howard wrote:

And what happens when you want to port that source code to a platform
that doesn't have a compiler with your extensions?

Most of it compiles in C++.

[Randy Howard]

In article <42************ ***********@new s.wanadoo.fr>,
ja***@jacob.rem comp.fr says...

Randy Howard wrote:

And what happens when you want to port that source code to a platform
that doesn't have a compiler with your extensions?

Most of it compiles in C++.

So you assume that all platforms even have a C++ compiler? If so,
then why not just write in C++ to begin with?

--
Randy Howard (2reply remove FOOBAR)
"Making it hard to do stupid things often makes it hard
to do smart ones too." -- Andrew Koenig

[Keith Thompson]

infobahn <in******@btint ernet.com> writes:

Keith Thompson wrote:

Since C already has malloc() and free(), new and delete wouldn't add
much value, but if I were designing a C-like language from scratch I'd
probably use new and delete *instead of* malloc() and free().

How would you deal with resizing? old?

I don't know. Since realloc() isn't used all that much, perhaps it
could remain a library function. I'll let you know when I get around
to designing a C-like language from scratch.

(Not sure what you mean by "old?".)

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Chris Croughton]

On 13 Feb 2005 03:50:04 -0800, we******@gmail. com
<we******@gmail .com> wrote:

Chris Croughton wrote:

On 12 Feb 2005 19:13:45 -0800, websnarf wrote:

> C has const. I don't quite see how C++'s consts are not redundant
> with either #define or enums. You can even make enums locally
> scoped.
Try declaring an enum with floating point type. Or using a const
int as a case value. I think that C++ should have found something
else to call them (and both C and C++ should have stopped the
overloading of the 'static' keyword, C++ even adds yet another
meaning to it), but typed constants are useful and don't have the
pitfalls of macros.

Ok, I see -- you really want are read-only variables. Fair enough.

No, I have read-only variables in C, that's what C const does. What I
would like is the C++ "named typed constants", they aren't variables at
all (they may not have any existence in storage in many cases).

> > declaring variables just before use etc.
>
> This is in C99, and personally I would rather have seen this
> *REMOVED* from C++, than added to C. It makes the job of reading
> code twice as hard -- if we wanted that, we might as well be using
> Perl. If you want to do "just in time constructors", wrap your
> code with additional scope.

Used properly (as in declaring loop variables only when they are
used) it makes it more readable, not less. I've seen a lot of
errors where someone has used a variable (often i or j) for a loop,
it has compiled (it was already declared) but it has done unexpected
things because it wasn't obvious that the variable was already in
use.

Ok, so then that's just it, then isn't it? Using it "properly" as you
say boils down to declarations of variables in the first expression of
a control statement such as for, while, if, or switch. Fine, but
that's a narrower extension than C++'s scheme.

What do you mean by "the first expression"?

Actually, using variable declaration mixed with code can be readble in
other cases as well, but in my opinion the use in a control statement
(and personally I only use them in for loops) is the most useful and the
one which definitely makes the code clearer. The ability to declare
them anywhere, as in C++, can not only make the code les clear but can
muddy the syntax itself (there are cases in C++ where it is ambiguous
whether something is a declaration or a statement).
At least my namespace extension remains intact. :)

IMO namespaces definitely make things clearer and are a Good Thing(tm).
Possibly the best feature of C++...

Chris C

[Keith Thompson]

Chris Croughton <ch***@keristor .net> writes:

On 12 Feb 2005 19:13:45 -0800, we******@gmail. com
<we******@gmail .com> wrote:

[...]

This is in C99, and personally I would rather have seen this *REMOVED*
from C++, than added to C. It makes the job of reading code twice as
hard -- if we wanted that, we might as well be using Perl. If you want
to do "just in time constructors", wrap your code with additional
scope.

Used properly (as in declaring loop variables only when they are used)
it makes it more readable, not less. I've seen a lot of errors where
someone has used a variable (often i or j) for a loop, it has compiled
(it was already declared) but it has done unexpected things because it
wasn't obvious that the variable was already in use.

You're talking about a different feature. For loop variables, you can
do the following:

...
for (i = 0; i < N; i ++) { ... }

Independently, you can do:

int i;
/* code that uses i */
int j;
/* code that uses j */

If abused, this can cause confusion, but it does add some flexibility.

Both features are supported in C99 and C++, and not in C90.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[infobahn]

Keith Thompson wrote:

infobahn <in******@btint ernet.com> writes:

Keith Thompson wrote:

Since C already has malloc() and free(), new and delete wouldn't add
much value, but if I were designing a C-like language from scratch I'd
probably use new and delete *instead of* malloc() and free().
How would you deal with resizing? old?

I don't know. Since realloc() isn't used all that much,

It isn't? Perhaps I use it more than most, then.
perhaps it
could remain a library function. I'll let you know when I get around
to designing a C-like language from scratch.

(Not sure what you mean by "old?".)

Nothing more sinister than "not exactly new" :-)

[Serve Lau]

"infobahn" <in******@btint ernet.com> wrote in message
news:42******** *******@btinter net.com...

Keith Thompson wrote:

Since C already has malloc() and free(), new and delete wouldn't add
much value, but if I were designing a C-like language from scratch I'd
probably use new and delete *instead of* malloc() and free().

How would you deal with resizing? old?

renew? :)

[infobahn]

Serve Lau wrote:

"infobahn" <in******@btint ernet.com> wrote in message
news:42******** *******@btinter net.com...

Keith Thompson wrote:

Since C already has malloc() and free(), new and delete wouldn't add
much value, but if I were designing a C-like language from scratch I'd
probably use new and delete *instead of* malloc() and free().

How would you deal with resizing? old?

renew? :)

Much better :-)

[Guillaume]

>>>Since C already has malloc() and free(), new and delete wouldn't add

much value, but if I were designing a C-like language from scratch I'd
probably use new and delete *instead of* malloc() and free().

How would you deal with resizing? old?

renew? :)

Come on, "real C++ programmers" don't resize. They just allocate more
objects and delete the old stuff (that is, when they don't forget to).

That leads to bloatware, but new is so "cute" compared to malloc().
lol ;-)