Re: bitwise comparators

[Ole-Hjalmar Kristensen <ohk@clustra.com>]

Keith Thompson <kst@cts.com> writes:

> Jeff Carter <jrcarter010@earthlink.net> writes:
> [...]
> > > With true arrays, do you mean out of bound checking, etc?  This can be done
> > > with _proper_ programming in C!
> > 
> > C does not have arrays; it only has different notations for address
> > arithmetic.
> 
> That's a slight exaggeration.  C does have array types and array
> objects.  For example this:
>     int a[10];
> declares a as an array of 10 ints, very much like Ada's
>     A: array(0 .. 9) of Integer;
> It does not, contrary to popular misconception, declare a as a
> pointer.
> 
> What often causes confusion is that, in most expression contexts, a
> reference to the name of an array object "decays" to a pointer to the
> array's first element.
> 
> C arrays are not first-class types, but they do exist.
> 
> -- 
> Keith Thompson (The_Other_Keith) kst@cts.com  <http://www.ghoti.net/~kst>
> San Diego Supercomputer Center           <*>  <http://www.sdsc.edu/~kst>
> Welcome to the last year of the 20th century.

I would say you are both right. C guarantees that in your example, a
is a constant pointer. I also guarantees that a[i] == *(a+i).
A somewhat curious fact is that i[a] == *(i+a) == *(a+i), so it is
completely legal C to write for instance : 9[a] = 13;
The only use of this is probably if you're competing in the obfuscated
C code contest :-)


Ole-Hj. Kristensen

-- 
E pluribus Unix