Re: Type of elements of std::string

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 27 Jan 2010 14:43:30 -0800 (PST)
Message-ID:
<8c3872a9-37cc-40c5-8462-2e8035d5160c@o9g2000yqa.googlegroups.com>
On Jan 27, 4:41 pm, "Leigh Johnston" <le...@i42.co.uk> wrote:

More generally, considering the first algorithm: the
no-argument form of istream::get returns an int in order to
return out of band data, e.g. EOF. Once that data has been
tested for and excluded, the resulting value must be
converted to a char. Formally, a rather complex operation,
since the resulting value is in the range 0...UCHAR_MAX,
which might not fit into a char (and if the results don't
fit, the behavior is implementation defined, and might
result in a signal). Practically, implementations which use
signed plain char will always ensure that this works, given
that it is such a standard idiom (in C, at least). But if
you really want to avoid it, something like:


Your insistence on describing the behaviour of rare corner
case implementations is unhelpful as it confuses the issue,
the fact that char ch = (unsigned char) foo; is implementation
defined behaviour is not justification for eschewing the use
of istream::read().


I never said it was (and I do use istream::read and
istream::write). Still, a competent programmer will want to
understand what he's doing, and what the restrictions and the
trade-offs are.

Please rejoin the real world.


In the real world, not every machine is a PC.

--
James Kanze

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