On Tue, 31 May 2011 14:20:20 -0400, eles <e...@eles.com> wrote:
== Quote from Mafi (m...@example.org)'s article
Am 31.05.2011 18:16, schrieb eles:
> Now, why:
>
> for(iterator from a[0] to a[N-1]){ //etc. }
> //let use the above notation for for(i=0; i<=N-1; i++)
>
> is acceptable, but sudden is no more acceptable to write
>
> a[for(iterator from 0 to N-1)]
>
> and one must use
>
> a[for(iterator from 0 to N]]
>
> in order to achieve exactly the same?
>
> The last two expressions are just mental placeholders for a
[0..N-1]
> and for a[0..N] respectively.
let
for(element from a[0] to a[n])
be a notation for
for(i=0; i < n; i++)
but then, assuming closed intervals, why do I have to write
a[i..n-1] to archive the same?
You see? This argument of yours is not really good.
Mafi
why not write:
for(i=0; i<=n-1; i++)
if n is unsigned int, and 0, then this becomes i = 0; i <= uint.max; i++
Basically, using subtraction in loop conditions is a big no-no. You are
much better off to write using addition:
i + 1 <= n
But then i < n looks so much better.
COnceptually, you are iterating elements from a[0] to a[n-1], this is
why index goes from 0 to n-1 (even if you write i<n).
What about if length of the array already equals UTYPE_MAX, ie. the
maximum value representable on the size_t? (I assume that indexes are
on size_t and they go from 0 to UTYPE_MAX).
First, size_t is the limit of your address space. You cannot have size_t
items in any slice.
Second, there are very very few use cases where size_t.max is used as an
iteration.
-Steve
