can i initialise variable name as '$'?

[nkrao123@gmail.]

Hi,

Earlier I studied that variable name should follow the below rulse

"Rules for Constructing Variable Names
(A) A variable name is any combination of 1 to 31 alphabets,
digits or underscores. Some compilers allow variable names
whose length could be up to 247 characters. Still, it would be
safer to stick to the rule of 31 characters. Do not create
unnecessarily long variable names as it adds to your typing
effort.
(B) The first character in the variable name must be an alphabet or
underscore.
(C) No commas or blanks are allowed within a variable name.
(D) No special symbol other than an underscore (as in gross_sal)
can be used in a variable name.
Ex.: si_int
m_hra
pop_e_89"





But

my doubt is i am able to compile the below program with the integer variable name as '$'

#include<stdio.h>
int main()
{
        int $;
        int j;
        $=10;
        printf ("%d\n",$);
        return 0;
}

can any one help me to know about this? is is correct variable declaration?

[quzah]

Is this going to be the new 'trick question' of the week? Tired of trying to swap variables without a temp, now they've got everyone asking if '$' is a valid variable name? Because I'm pretty sure someone asked that last week too.


Quzah.

[Salem]

Dollar Signs - Using the GNU Compiler Collection (GCC)

And

$ cat foo.c
#include<stdio.h>
int main()
{
        int $;
        int j;
        $=10;
        printf ("%d\n",$);
        return 0;
}

$ gcc foo.c

$ gcc -Wall -ansi -pedantic foo.c
foo.c:4:13: warning: '$' in identifier or number
foo.c: In function ‘main’:
foo.c:5: warning: unused variable ‘j’

Understand that there are always differences between what the standard says (and what ALL compilers should support), and what your current compiler will let you get away with (and what any other compiler can legitimately reject).

If you program within the limits of the standard, you maximise your chances of having your code work on other compilers, and (importantly), you maximise your chance of being able to USE other compilers without a lot of tedious re-learning every time the environment changes.

[nkrao123@gmail.]

HI salem,

is it depend on compiler designs ? am i right?

[whiteflags]

It's actually dependant on the environment. All identifier names that a conforming C compiler must support have an initial nondigit character, followed by any of all the lower case letters or uppercase letters, digits, or also including the underscore. I dug up the information for someone else once in the C standard, I'm sure you can do that if you try.

[Salem]

The variable naming rules are specified by the C standards.
C Draft Standards

Anything else your compiler seems to give you is an implementation detail that is NOT portable.
Use it if you want, but don't come crying when you stop using foo compiler, and start using bar compiler.

[CommonTater]

Is this going to be the new 'trick question' of the week? Tired of trying to swap variables without a temp, now they've got everyone asking if '$' is a valid variable name? Because I'm pretty sure someone asked that last week too.
Quzah.

What I'm wondering is why new programmers seem to automatically leap to cheats and tricks... there's a guy in the Windows forum saying he's a new programmer and asking about alternate NTFS streams, like that's something we do on an ordinary day... then there's that bunch who want to write self-booting code or access the hardware directly...

If I were asked, I'd advise them to learn programming *at all* before they even think about messing with hacks, cracks and flacks...

Yes you can have a variable named $ in C ... but how does that make you a better programmer?