c pointers (ptrdiff_t)

[andy_dufresne]

have posted the question here:

http://groups.google.com/group/progr...b58c897f890930

[Mark McIntyre]

On 30 Nov 2005 11:24:06 -0800, in comp.lang.c , "andy_dufresne"
<ak*******@gmail.com> wrote:

have posted the question here:

http://groups.google.com/group/progr...b58c897f890930

Then please post it here, too, assuming its topical.

--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.ungerhu.com/jxh/clc.welcome.txt>

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[Brytison]

can't replace to other site, just here only, post you question at here
better.

"andy_dufresne" <ak*******@gmail.com>
??????:11*********************@g47g2000cwa.googleg roups.com...

have posted the question here:

http://groups.google.com/group/progr...d/75b58c897f89
0930

[andy_dufresne]

sorry abt that.
here's the question:

hi,
i'd a question abt taking the difference between two pointers.
for eg: if you have 2 char pointers pointing to members of an array,
you
advance one till you encounter a space then take the difference between
the two, will give the correct length of the string irrespective of
whether char is represented by 2 bytes (like in unicode)?? i believe it
would give the correct length, because the compiler is responsible for
scaling the difference when one advances a pointer to point to the next
element like ptr++, or is it that pointer difference (subtraction
between two
pointers to members of the same array) is not pointer arithmetic and we
need
to scale it??

eg problem:
Orig string - char *s;
Ptrs, char *start = s, *end = s;
int length;
while(!isspace(*end))
end++;
length = end - start;

is this mentioned somewhere in the c std?? if so could someone pt me in
the right direction.

Thanks.