Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Initializing sum to zero wouldn't compile |
| Date | 2015-08-26 11:44 -0700 |
| Organization | None to speak of |
| Message-ID | <lnio81x52u.fsf@kst-u.example.com> (permalink) |
| References | (3 earlier) <c0acb3a0-aa9d-43aa-b4ae-c00e7622e43a@googlegroups.com> <4m3itahdhql900hjkegsqtflvsajjsd0hp@4ax.com> <b5f85a9f-fbbb-4a6e-9df8-7048a301428e@googlegroups.com> <r21rtat1fbpjsu4l4eru2ae1l0j5336eiu@4ax.com> <863bc31e-b8f9-4f8d-8d43-a99cf48cf849@googlegroups.com> |
Alla _ <modelling.data@gmail.com> writes:
[attribution missing]
>> WHY is a floating point number with a fractional value of 0 considered
>> invalid?
>
> Mathematically and scientifically it is a float number, but given my
> lack of knowledge, I couldn't yet find the way to test both for
> integers and for floats with zeros after decimal points.
Are you trying to distinguish between an input like "2.0" and an input
like "2"?
If you read input into a floating-point object, you'll get exactly the
same value for either input. Once you've done that, you've lost any
information about what the input looked like as a sequence of
characters.
You can, if you like, read the input *as a string*, determine whether it
matches the syntax of a floating-point constant or an integer constant,
and take different action from there, converting the string "2" to an
integer value or the string "2.0" to a floating-point value.
But I'm not at all sure why you'd want to do that. If a program asks
for a floating-point number as input, C's standard *scanf() and strto*()
function accept either "2" and "2.0" as valid input -- and IMHO your
program *should* accept "2" as floating-point input. If you want to
make that distinction, you can, but I don't think yhou should. It
violates the Principle of Least Surprise; I *expect* to be able to type
"2" and have it interpreted as 2.0.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-21 04:39 -0700
Re: Initializing sum to zero wouldn't compile James Kuyper <jameskuyper@verizon.net> - 2015-08-21 07:54 -0400
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-21 05:27 -0700
Re: Initializing sum to zero wouldn't compile Keith Thompson <kst-u@mib.org> - 2015-08-21 10:28 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-21 11:15 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-21 05:30 -0700
Re: Initializing sum to zero wouldn't compile Ike Naar <ike@iceland.freeshell.org> - 2015-08-21 12:40 +0000
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-21 11:16 -0700
Re: Initializing sum to zero wouldn't compile Siri Cruz <chine.bleu@yahoo.com> - 2015-08-21 07:41 -0700
Re: Initializing sum to zero wouldn't compile Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2015-08-21 10:56 -0400
Re: Initializing sum to zero wouldn't compile Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2015-08-21 09:28 -0600
Re: Initializing sum to zero wouldn't compile Barry Schwarz <schwarzb@dqel.com> - 2015-08-21 10:02 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-21 11:21 -0700
Re: Initializing sum to zero wouldn't compile Barry Schwarz <schwarzb@dqel.com> - 2015-08-21 22:27 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-22 02:25 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-22 03:50 -0700
Re: Initializing sum to zero wouldn't compile Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-22 13:18 +0100
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-22 11:21 -0700
Re: Initializing sum to zero wouldn't compile Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-22 21:55 +0100
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-26 01:36 -0700
Re: Initializing sum to zero wouldn't compile Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-26 11:24 +0100
Re: Initializing sum to zero wouldn't compile Barry Schwarz <schwarzb@dqel.com> - 2015-08-22 17:17 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-26 01:26 -0700
Re: Initializing sum to zero wouldn't compile Barry Schwarz <schwarzb@dqel.com> - 2015-08-26 02:27 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-26 04:21 -0700
Re: Initializing sum to zero wouldn't compile Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-26 12:37 +0100
Re: Initializing sum to zero wouldn't compile Richard Heathfield <rjh@cpax.org.uk> - 2015-08-26 13:06 +0100
Re: Initializing sum to zero wouldn't compile Bartc <bc@freeuk.com> - 2015-08-26 13:43 +0100
Re: Initializing sum to zero wouldn't compile Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-26 14:03 +0100
Re: Initializing sum to zero wouldn't compile Richard Heathfield <rjh@cpax.org.uk> - 2015-08-26 14:06 +0100
Re: Initializing sum to zero wouldn't compile Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 15:14 -0700
Re: Initializing sum to zero wouldn't compile Keith Thompson <kst-u@mib.org> - 2015-08-26 11:38 -0700
Re: Initializing sum to zero wouldn't compile Keith Thompson <kst-u@mib.org> - 2015-08-26 11:44 -0700
Re: Initializing sum to zero wouldn't compile Barry Schwarz <schwarzb@dqel.com> - 2015-08-22 10:49 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-22 11:16 -0700
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-29 07:19 -0700
Re: Initializing sum to zero wouldn't compile Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-29 15:35 +0100
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-30 02:11 -0700
Re: Initializing sum to zero wouldn't compile Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-30 12:28 +0100
Re: Initializing sum to zero wouldn't compile Keith Thompson <kst-u@mib.org> - 2015-08-30 15:02 -0700
Re: Initializing sum to zero wouldn't compile Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-08-30 22:36 +0100
Re: Initializing sum to zero wouldn't compile Keith Thompson <kst-u@mib.org> - 2015-08-30 16:10 -0700
Re: Initializing sum to zero wouldn't compile Bartc <bc@freeuk.com> - 2015-08-31 00:14 +0100
Re: Initializing sum to zero wouldn't compile Keith Thompson <kst-u@mib.org> - 2015-08-30 19:56 -0700
Re: Initializing sum to zero wouldn't compile Bartc <bc@freeuk.com> - 2015-08-29 16:57 +0100
Re: Initializing sum to zero wouldn't compile Bartc <bc@freeuk.com> - 2015-08-29 17:37 +0100
Re: Initializing sum to zero wouldn't compile Alla _ <modelling.data@gmail.com> - 2015-08-30 02:14 -0700
csiph-web