In the book "Complete Reference of C" it is mentioned that char is by default unsigned.
But i am trying to verify this with GCC as well as visual studio. It is taking it as signed by default.
which one is correct
+9
A:
The book is wrong. The standard does not specify if plain char is signed or unsigned.
In fact, the standard defines three distinct types: char, signed char, and unsigned char. If you #include <limits.h> and then look at CHAR_MIN, you can find out if plain char is signed or unsigned (if CHAR_MIN is less than 0 or equal to 0), but even then, the three types are distinct as far as the standard is concerned.
Alok
2010-01-13 06:48:09
@Alok: the same is not true for some other datatypes, for example `int` means `signed int` always, right? Apart from `char`, what other datatypes have the same confusion in `C`?
Lazer
2010-03-28 11:15:24
@eSKay: yes, `char` is the only type that can be signed or unsigned. `int` is equivalent to `signed int` for example.
Alok
2010-03-29 00:54:19
+4
A:
As Alok points out, the standard leaves that up to the implementation.
For gcc, the default is signed, but you can modify that with -funsigned-char. You can also explicitly ask for signed characters with -fsigned-char.
On MSVC, the default is signed but you can modify that with /J.
R Samuel Klatchko
2010-01-13 06:51:52
Interesting that Schildt's description doesn't match MSVC's behavior since his books are usually geared toward MSVC users. I wonder if MS changed the default at some point?
Michael Burr
2010-01-13 07:17:14
+3
A:
The standard has this to say about the signed-ness of type char:
The implementation shall define char to have the same range, representation, and behavior as either signed char or unsigned char.
and in a footnote:
CHAR_MIN, defined in<limits.h>, will have one of the values0orSCHAR_MIN, and this can be used to distinguish the two options. Irrespective of the choice made,charis a separate type from the other two and is not compatible with either.
Michael Burr
2010-01-13 07:09:44