Re: Array of pointers. How to check index without failure?

From:

Pete Becker <pete@versatilecoding.com>

Newsgroups:

comp.lang.c++

Date:

Fri, 3 Aug 2007 19:41:28 -0400

Message-ID:

<2007080319412816807-pete@versatilecodingcom>

On 2007-08-03 19:11:30 -0400, Andre Kostur <nntpspam@kostur.net> said:

Gianni Mariani <gi3nospam@mariani.ws> wrote in news:46b3a088$0$31411
$5a62ac22@per-qv1-newsreader-01.iinet.net.au:

James Kanze wrote:
...

Be careful using the "if(p)" syntax; it does an integer
comparison on the pointer which isn't valid on all platforms.

No it doesn't. The condition in an if must have type bool.
There is an implicit conversion of pointer to bool, which is
basically the equivalent of "p != NULL". Code like "if (p)" may
be unreadable, and it's not the sort of thing you'd ever see in
well written C++, but it is perfectly legal and well defined.

if (p) *IS* readable. There is nothing ambiguous, unclear or not "well
written" about it other than it's missing one of the silliest standard
macros since the beginning C compared to if (p != NULL).

I disagree. I prefer the explicit test against NULL. (I'd prefer it even
more if they standardize on a keyword nulptr). I dislike testing implicit
conversions to bool, so the only time I write "if (p)" is only if p is a
bool. If it is anything else, I'll write out the full test; "if (p != 0)"
for example.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)