Hi All,
When I run the below program in MSVC, I get the output as
1
4
Could you tell me why sizeof 'A' is taken as 4? Is it standard defined
or compiler specific?
Thanks,
Nishu
/*************** *************** ********/
#include<stdio. h>
int main(void)
{
const char ch = 'A';
printf("%d\n", sizeof ch);
printf("%d\n", sizeof 'A');
return 0;
}
/*************** ****/
Jul 10 '07
58  7204 
jacob navia wrote:
>
As Pietro said, 'A' is considered an int in C, not
a character. This is one of the many inconsistencies of the
language that you must learn by heart.
Just curious: With what is the int-ness of 'A' "inconsiste nt?"
--
Eric Sosman es*****@ieee-dot-org.invalid
Eric Sosman wrote:
jacob navia wrote:
>>
As Pietro said, 'A' is considered an int in C, not
a character. This is one of the many inconsistencies of the
language that you must learn by heart.
Just curious: With what is the int-ness of 'A' "inconsiste nt?"
With it being a character of course.
jacob navia wrote:
Eric Sosman wrote:
>jacob navia wrote:
>>>
As Pietro said, 'A' is considered an int in C, not
a character. This is one of the many inconsistencies of the
language that you must learn by heart.
Just curious: With what is the int-ness of 'A' "inconsiste nt?"
With it being a character of course.
It's consistent with getchar/putchar - I always thought that was the reason.
Richard Harnden wrote:
jacob navia wrote:
Eric Sosman wrote:
jacob navia wrote:
As Pietro said, 'A' is considered an int in C, not
a character. This is one of the many inconsistencies of the
language that you must learn by heart.
Just curious: With what is the int-ness of 'A' "inconsiste nt?"
With it being a character of course.
It's consistent with getchar/putchar - I always thought that was the reason.
They were probably designed after the core language features were
decided upon.
getchar/putchar could very well return an int while character
constants could be of type char.
Richard Harnden <ri*****@oninit .comwrites:
jacob navia wrote:
Eric Sosman wrote:
jacob navia wrote:
As Pietro said, 'A' is considered an int in C, not
a character. This is one of the many inconsistencies of the
language that you must learn by heart.
Just curious: With what is the int-ness of 'A' "inconsiste nt?"
With it being a character of course.
It's consistent with getchar/putchar - I always thought that was the reason.
Is it? putchar('\xFE') doesn't do the right thing if char is signed.
Yours,
--
Jean-Marc
jacob navia wrote On 07/10/07 08:40,:
Eric Sosman wrote:
>>jacob navia wrote:
>>>As Pietro said, 'A' is considered an int in C, not
a character. This is one of the many inconsistencies of the
language that you must learn by heart.
Just curious: With what is the int-ness of 'A' "inconsiste nt?"
With it being a character of course.
... but since it *isn't* a character, you might just
as well say its int-ness is inconsistent with it being
a struct tm. The int-ness of 'A' may be surprising[*],
but I can't think of any convention or practice elsewhere
in the language that establishes a pattern with which
it could be inconsistent.
[*] Or maybe not, when you consider the usual
arithmetic conversions (6.3.1.8). With the exception
of sizeof, every operator[**] you could apply to a
char-type 'A' would promote its value to int or unsigned
int anyhow.
[**] If I've overlooked something, I'm confident
someone will remind me.
-- Er*********@sun .com
On Tue, 10 Jul 2007 14:40:52 +0200, in comp.lang.c , jacob navia
<ja***@jacob.re mcomp.frwrote:
>Eric Sosman wrote:
>jacob navia wrote:
>>>
As Pietro said, 'A' is considered an int in C, not
a character. This is one of the many inconsistencies of the
language that you must learn by heart.
Just curious: With what is the int-ness of 'A' "inconsiste nt?"
With it being a character of course.
Where does it say that characters are the same size as chars?
--
Mark McIntyre
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan
Mark McIntyre <ma**********@s pamcop.netwrite s:
On Tue, 10 Jul 2007 14:40:52 +0200, in comp.lang.c , jacob navia
<ja***@jacob.re mcomp.frwrote:
>>Eric Sosman wrote:
>>jacob navia wrote:
As Pietro said, 'A' is considered an int in C, not
a character. This is one of the many inconsistencies of the
language that you must learn by heart.
Just curious: With what is the int-ness of 'A' "inconsiste nt?"
With it being a character of course.
Where does it say that characters are the same size as chars?
Yeah, how could *anyone* get confused by *that*?!?!?!?
<rolls eyes>
It was a dubious decision, for whatever reason, to default a character
constant to an int and not a char. Someone better versed in the history
gave a better point of view elsewhere in the thread. rl*@hoekstra-uitgeverij.nl (Richard Bos) writes:
Nishu <na**********@g mail.comwrote:
>On Jul 10, 1:07 am, Pietro Cerutti wrote:
Nishu wrote:
Could you tell me why sizeof 'A' is taken as 4? Is it standard defined
or compiler specific?
Because 'A' alone is an int.
OK. What is the reason for considering it as int? I think we use
single quotes to say that it is a char.
For hysterical raisins, the type of a character constant is int. It's
one of the (IMO few) areas where C++ improves on C: in that language,
it's a char. But not, unfortunately, in C.
It makes very little difference in C; expressions of type char are
almost always promoted to int anyway. Applying sizeof to a character
constant is nearly the only case where the different shows up.
<OT>It matters more in C++ because of overloading; func('A') and
func(65) might call two different functions.</OT>
This is question 8.9 in the comp.lang.c FAQ.
--
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."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
Eric Sosman <Eric.Sos...@su n.comwrote:
jacob navia wrote On 07/10/07 08:40,:
Eric Sosman wrote:
jacob navia wrote:
As Pietro said, 'A' is considered an int in C,
not a character. This is one of the many
inconsistencies of the language that you must
learn by heart.
>
Just curious: With what is the int-ness
of 'A' "inconsiste nt?"
With it being a character of course.
... but since it *isn't* a character,
'A' could not possibly be thought of as character?!
Even if you 'know better', I can't believe the obviousness
of the expectation eludes you.
Note that C++ didn't make 'A' a char to support overloading.
That is incidental. C++ made 'A' a char because it's common
sense to think of and _use_ 'A' as a character. The
situation is no different in C.
you might just as well say its int-ness is inconsistent
with it being a struct tm.
If it had two distinct types simultaniously, I would say it
was inconsistent, yes.
The int-ness of 'A' may be surprising[*],
It is surprising.
but I can't think of any convention or practice elsewhere
in the language that establishes a pattern with which
it could be inconsistent.
Can you think of any convention or practice elsewhere in
the language that would established a pattern with which
'A' being a character would be inconsistent?
[*] Or maybe not, when you consider the usual
arithmetic conversions (6.3.1.8).
And why would making 'A' a character be inconsistent with
the usual arithmetic conversions? C++ programmers are no
more hampered in writing (*p - '0') than C programmers.
With the exception of sizeof, every operator[**] you
could apply to a char-type 'A' would promote its value
to int or unsigned int anyhow.
So let me turn that back at you. If it's going to happen
anyhow, again I ask, why would making 'A' a char cause
any harm?
[**] If I've overlooked something, I'm confident
someone will remind me.
Here's a question for you: If it's so obvious why 'A'
should be an int, why then does '\xfe' have no less
than 4 distinct possible values, depending on the
implementation?
C was designed for a purpose. Being a useful and
intuitive language for beginners wasn't one of them.
;-)
--
Peter This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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