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From: seebs@plethora.net (Peter Seebach)
Subject: Re: Mixing declarations and statements (Re: Porting (was ADA and
 Pascal etc))
Date: 1997/11/04
Message-ID: <63nlk6$h0e$1@darla.visi.com>#1/1
X-Deja-AN: 287916243
References: <34557f2b.1934172@news.mindspring.com>
 <63d5l4$tub$1@helios.crest.nt.com> <878495810snz@genesis.demon.co.uk>
 <swutch@kaa.gr.osf.org>
Organization: Plethora Internet
NNTP-Posting-Date: 04 Nov 1997 11:22:14 CST
Newsgroups: comp.lang.ada,comp.lang.c
Date: 1997-11-04T11:22:14-06:00
List-Id: <comp.lang.ada>


In article <swutch@kaa.gr.osf.org>,
�amonn McManus <emcmanus@gr.opengroup.org> wrote:
>with the exciting new feature you can write:

>    switch (thing) {
>    case one:
>	int x = whatever();
>	use(x);
>	break;
>    case two:
>	int x = maybe();
>	use(x);
>	break;
>    }

>Except I very much hope that you can't, since that would be a multiple
>declaration of x.

I think you are correct.

>Presumably the new C will allow the first
>declaration but require the `int' to be left off the second, turning
>it back into a lowly statement.

Yes.

>That's terrible programming practice of
>course because you're having the meaning of one switch case depend on
>the way another one was written.

So, what you might do is
	switch (thing) {
	int x;
	case one:
	...
	}
and, of course, you can't count on x being initialized, because you'll
be jumping in past the initializer.

>Nonetheless the new C feature is easy to implement and understand and is
>fairly often useful.

That's my reading of it.  I still slightly prefer blocks, so I can
clearly end the scope of a declaration, but that's just a matter
of personal style.

-s
-- 
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Copyright 1997.  All rights reserved.  This was not written by my cat.
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