"Robert Gamble" <rgamble99@gmail.com> writes:[color=blue]
> Joe Wright wrote:[color=green]
>> Robert Gamble wrote:[color=darkred]
>> > serrand wrote:
>> >>is there a way in order to write binary numbers as hexa or octal in c ?
>> >
>> > I assume you are asking whether C supports a binary constant notation
>> > like it does for octal and hexadecimal numbers, the answer is no. It
>> > is not too difficult to create macros that allow you to do this though.
>> >
>> > Robert Gamble
>> >[/color]
>> Can you give me an example of a macro to do this? Thanks.[/color]
>
> Absolutely. I have seen a couple of variations (which I can't seem to
> locate right now) but the below example gets the gist of the technique
> across:
>
> #include <stdio.h>
>
> #define A(x) 0 ## x ## ULL
> #define B(x) ((A(x) & 01ULL) + (2*(!!((A(x) & 010ULL)))) + (4*(!!((A(x)
> & 0100ULL)))))
>
> int main (void) {
> printf("%llu\n", B(110));
> return 0;
> }
>
> This version handles up to 3 digit binary numbers, extending it to
> handle more is trivial.
> This isn't perfect as it can only represent a range limited by the
> highest octal representation which is why the ULL modifier is there but
> it is good enough for some.[/color]
That's a very clever technique. Note that "very clever" is not
necessarily a good thing.
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 W. Kernighan
(Yes, that's the K in K&R.)
It would be nice, IMHO, if C supported binary constants, probably
using a syntax like 0b11001001. Since it doesn't, the best
alternative is to use octal or hexadecimal constants; a knowledgable
reader knows that each digit represents 3 or 4 bits.
--
Keith Thompson (The_Other_Keith)
kst-u@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.
