Re: parametized numerical constants

From:

"Alf P. Steinbach" <alfps@start.no>

Newsgroups:

comp.lang.c++

Date:

Thu, 25 Mar 2010 15:51:09 +0100

Message-ID:

<hoft54$fmb$1@news.eternal-september.org>

* Juha Nieminen:

Alf P. Steinbach wrote:

* Juha Nieminen:

Why would you *purposefully* want to initialize the variable with
0.100000001490116 when what you want is 0.1?

The OP might want to do that to avoid warnings.

Well, that's the wrong solution to avoid the warning, and suggesting
it as a viable solution is irresponsible.

Not at all, IMO.

But since you're not offering any reasoning as to why you think that, the best I
can do, in addition to the reasoning I've already presented, is to point to you
towards Pete Becker's post else-thread; with that it's opinion (that it might be
a reasonable thing to do) against opinion (irresponsible), with 2 against 1. :-)

OK, it's fallacy to take such things to a vote, but really, I think charges such
as "irresponsible" should be accompanied by at least some modicum of reasoning.

Just because a compiler happens to not issue a warning about the
precision loss of converting "0.1" to float and then to double doesn't
mean it's the correct thing to do.

No, it means that for that compiler (which means just about every compiler) it's
a practical solution to the stated problem. Unless there are strong reasons not
to do it. There are also other practical solutions, but involving more typing.

Cheers,

- Alf