Need some explanation

[rahul8143]

hello,
1) First how following program get executed i mean how output is
printed and also why following program gives different output in Turbo
C++ compiler and Visual c++ 6 compiler?
void main()
{
int val=5;
printf("%d %d %d %d",val,--val,++val,val--);
}
under turbo compiler its giving
4 4 5 5
and under visual c++ its
5 5 6 5

2) How to evaluate following statement
int val =5;
val =- --val - val-- - --val;

[Richard Heathfield]

Chris Hills wrote:

In article <42************ ***@yahoo.com>, CBFalconer
<cb********@yah oo.com> writes

Tobias is missing the point that the subject of c.l.c is _portable_
C code, as defined by the standards from K&R through C89, C90, C95,
and C99. If you have to specify the implementation, you are
off-topic here.

Does it say that in the charter for this NG?

Yes.

And before you ask, I have it locked away in a cupboard here at MI5
headquarters, where only authorised personnel are able to read it.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
mail: rjh at above domain

[Chris Hills]

In article <db**********@n wrdmz02.dmz.ncs .ea.ibs-infra.bt.com>, Richard
Heathfield <in*****@addres s.co.uk.invalid > writes

Far too much is written on the subject of void main. This is really simple
to get right - even the most trivial reading of the Standard shows that an
int return type is the natural choice for C programs that are intended to
be portable, so why not just use int?

I agree. The only time you would not use int is in a free-standing
system where there is nothing to return to. Otherwise there is no
justification for not doing it.
--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
/\/\/ ch***@phaedsys. org www.phaedsys.org \/\/\
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

[Chris Hills]

In article <db**********@n wrdmz02.dmz.ncs .ea.ibs-infra.bt.com>, Richard
Heathfield <in*****@addres s.co.uk.invalid > writes

Chris Hills wrote:

In article <42************ ***@yahoo.com>, CBFalconer
<cb********@yah oo.com> writes

Tobias is missing the point that the subject of c.l.c is _portable_
C code, as defined by the standards from K&R through C89, C90, C95,
and C99. If you have to specify the implementation, you are
off-topic here.

Does it say that in the charter for this NG?

Yes.

Then please post it. Seriously I should be interested to see it.
And before you ask, I have it locked away in a cupboard here at MI5
headquarters , where only authorised personnel are able to read it.

The only MI5 that I am aware of is a Graphics company Mike India 5 Ltd
(co number. 02907648 ) by Junction 2 of the M4.
(used to be www.mi-5.co.uk but it is a blank page now)

Though you do work for a highly connected organisation :-)
I will ask for the charter at next time I am passing the office

--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
/\/\/ ch***@phaedsys. org www.phaedsys.org \/\/\
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

[pete]

Chris Hills wrote:

In article <db**********@n wrdmz02.dmz.ncs .ea.ibs-infra.bt.com>,
Richard Heathfield <in*****@addres s.co.uk.invalid > writes

Chris Hills wrote:

the charter for this NG?

And before you ask, I have it locked away in a cupboard here at MI5
headquarters , where only authorised personnel are able to read it.

The only MI5 that I am aware of is a Graphics company Mike India 5 Ltd

MI5 is his cover. You can easily deduce from his activities
that he really works for MI6.

http://www.mjnewton.demon.co.uk/bond/jbssfaq.htm

--
pete

[Joe Wright]

pete wrote:

Chris Hills wrote:

In article <db**********@n wrdmz02.dmz.ncs .ea.ibs-infra.bt.com>,
Richard Heathfield <in*****@addres s.co.uk.invalid > writes

Chris Hills wrote:
the charter for this NG?
And before you ask, I have it locked away in a cupboard here at MI5
headquarters , where only authorised personnel are able to read it.

The only MI5 that I am aware of is a Graphics company Mike India 5 Ltd

MI5 is his cover. You can easily deduce from his activities
that he really works for MI6.

http://www.mjnewton.demon.co.uk/bond/jbssfaq.htm

At MI6 there is Richard Bond, 006-7/8. He is under such deep cover that
nobody knows how to fix his Martini. He drives a really cool 1992 Mazda
Miada. Is that our man? :-)

Welcome back Richard.

--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Keith Thompson]

Chris Hills <ch***@phaedsys .org> writes:

In article <db**********@n wrdmz02.dmz.ncs .ea.ibs-infra.bt.com>, Richard
Heathfield <in*****@addres s.co.uk.invalid > writes

Far too much is written on the subject of void main. This is really simple
to get right - even the most trivial reading of the Standard shows that an
int return type is the natural choice for C programs that are intended to
be portable, so why not just use int?

I agree. The only time you would not use int is in a free-standing
system where there is nothing to return to. Otherwise there is no
justification for not doing it.

Just out of curiosity, are there any freestanding implementations that
accept
void main(void) { }
that *don't* accept
int main(void) { return 0; }
(with the same effect)? If not, there's even less reason to use void
main() -- though I suppose if you're certain your code will only ever
be compiled on a system that accepts void main(), there's no much
reason not to use it.

--
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 Hills]

In article <ln************ @nuthaus.mib.or g>, Keith Thompson <kst-
[e-mail]> writes

Chris Hills <ch***@phaedsys .org> writes:

In article <db**********@n wrdmz02.dmz.ncs .ea.ibs-infra.bt.com>, Richard
Heathfield <in*****@addres s.co.uk.invalid > writes

Far too much is written on the subject of void main. This is really simple
to get right - even the most trivial reading of the Standard shows that an
int return type is the natural choice for C programs that are intended to
be portable, so why not just use int?

I agree. The only time you would not use int is in a free-standing
system where there is nothing to return to. Otherwise there is no
justification for not doing it.

Just out of curiosity, are there any freestanding implementations that
accept
void main(void) { }
that *don't* accept
int main(void) { return 0; }
(with the same effect)? If not, there's even less reason to use void
main() -- though I suppose if you're certain your code will only ever
be compiled on a system that accepts void main(), there's no much
reason not to use it.

Good point. I am not sure if they would actually accept it. Never tried
it.

However it is incorrect as it implies main can return which it can't.
In many situations a return from main is fatal.

In a free-standing system it would be as incorrect to use int main as it
is to use void main in a hosted environment. Though there is less harm
in using void main in a hosted environment.

The int return in a hosted system is stylistic. There is often nothing
returned so having a void makes no difference. If you do need to return
something then you have to put it in.

In a free-standing system having a return the implication is that the
program could terminate. This is not something you want to have even as
a fleeting thought. Many free standing systems are embedded systems and
safety critical.

Personally I would never write a hosted application without the int
return but I would never put a return type other than void on a free-
standing system.

--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
/\/\/ ch***@phaedsys. org www.phaedsys.org \/\/\
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

[Walter Roberson]

In article <86************ **@phaedsys.dem on.co.uk>,
Chris Hills <ch***@phaedsys .demon.co.uk> wrote:

In a free-standing system it would be as incorrect to use int main as it
is to use void main in a hosted environment. In a free-standing system having a return the implication is that the
program could terminate. This is not something you want to have even as
a fleeting thought. Many free standing systems are embedded systems and
safety critical.

What you are indicating is that ANSI/ISO should -define- main() for
freestanding implementations as an infinite loop, to prevent
the -possibility- that it might exit -- because the application just
might happen to be safety critical. And that the default signal
handling should be "re-invoke the program entry point" instead of
"terminate" .
What was the name of that new language element again?

exit_from_embed ded_program_Yes _Yes_Yes_I_have _thought_about_ the_possible_im plact_on_safety _and_I_still_wa nt_to_do_it_and _I_will_take_pe rsonal_responsi bility (
struct *Here_are_my_la wyers_contact_d etails_so_I_can _be_personally_ sued_if_I_was_w rong_and_should _not_have_allow ed_the_program_ to_exit )
--
The rule of thumb for speed is:

1. If it doesn't work then speed doesn't matter. -- Christian Bau

[Chris Torek]

In article <86************ **@phaedsys.dem on.co.uk>
Chris Hills <ch***@phaedsys .demon.co.uk> wrote:

In a free-standing system having a return the implication is that the
program could terminate. ...

Many freestanding system programs *do* terminate, and correctly so.
(Many others do not, also correctly so.) I would argue that this is
irrelevant:

A hosted C system (that conforms to either C89 or C99) is *guaranteed*
to accept, and do something at least marginally useful with, an
"int main" function with a return value that is one of the three
standard values (0, EXIT_SUCCESS, and EXIT_FAILURE).

A freestanding C system need not even *use* a function named
main().

My personal preference (though I admit I do not always get my way
:-) ) is to write hosted applications using "int main" and freestanding
applications using *no* function named "main" at all. When it is
done this way, I find there is minimal confusion and maximal
bug-reduction. (I write a lot of code that runs in one or the
other situation, or sometimes even both. When the code needs to
run on both freestanding and hosted systems, the "int main()" piece
is usually quite short, as is the freestanding system's "main-like"
entry point: both set up the environment needed to call the "real"
program start. In most cases, the unused stub -- the function
named main() in the freestanding code, which is unused there because
the program starts in start(); and start() in the hosted code,
which is unused there because the program starts in main() -- can
be left in, although for memory-footprint sake, one may often want
to omit main() in the embedded/freestanding version.)
--
In-Real-Life: Chris Torek, Wind River Systems
Salt Lake City, UT, USA (40°39.22'N, 111°50.29'W) [phone]
email: forget about it http://web.torek.net/torek/index.html
Reading email is like searching for food in the garbage, thanks to spammers.

[Richard Heathfield]

Chris Hills wrote:

In article <db**********@n wrdmz02.dmz.ncs .ea.ibs-infra.bt.com>, Richard
Heathfield <in*****@addres s.co.uk.invalid > writes

Chris Hills wrote:

In article <42************ ***@yahoo.com>, CBFalconer writes
If you have to specify the implementation, you are
off-topic here.
Does it say that in the charter for this NG?
Yes.

Then please post it. Seriously I should be interested to see it.

But hang on, I covered that...

And before you ask, I have it locked away in a cupboard here at MI5
headquarter s, where only authorised personnel are able to read it.

The only MI5 that I am aware of is a Graphics company Mike India 5 Ltd
(co number. 02907648 ) by Junction 2 of the M4.
(used to be www.mi-5.co.uk but it is a blank page now)

Yes, very blank; we're not particularly tolerant of competitors.

Though you do work for a highly connected organisation :-)
I will ask for the charter at next time I am passing the office

Excellent. You will be expected. Please make sure your affairs are in order
before calling.
--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
mail: rjh at above domain