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From: "Vinzent Hoefler" <0439279208b62c95f1880bf0f8776eeb@t-domaingrabbing.de>
Newsgroups: comp.lang.c++,comp.lang.ada
Subject: Re: Why use C++?
Date: Mon, 15 Aug 2011 14:59:38 +0200
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Date: 2011-08-15T14:59:38+02:00
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Stuart Redmann wrote:

> Stuart Redmann wrote:
> [snip]
>> > Be honest, how often do you really _want_ a wrapping int?
>
> On 12 Aug. Vinzent Hoefler wrote:
>> Thinking indices instead of pointers, quite often, actually.
>
> Could you please provide some example? Seriously, I'm really
> interested in the usage of wrapping types since in the last ten years
> I have not felt the need for wrapping ints at all (well, maybe two or
> three times).

Indexing of a double-buffer would be the most simple example. Switching
between both halves can then be expressed by a simple increment instead of
conditional statements, or explicit masking of the upper bits.

And while extending the data structure to a ring-buffer, masking does only
work for ring-buffers with a size of power-of-two. So, using a modular type
could even provide a slight performance gain in the special case while the
code still works in the general case.


Vinzent.

-- 
f u cn rd ths, u cn gt a gd jb n cmptr prgrmmng.