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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: question about nullptr
Date: Tue, 09 Jul 2024 03:57:49 -0700
Organization: A noiseless patient Spider
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Michael S <already5chosen@yahoo.com> writes:

> On Tue, 9 Jul 2024 02:49:49 -0000 (UTC)
> Kaz Kylheku <643-408-1753@kylheku.com> wrote:
>
>> On 2024-07-08, Michael S <already5chosen@yahoo.com> wrote:
>>
>>> On Sun, 07 Jul 2024 15:17:34 -0700
>>> Keith Thompson <Keith.S.Thompson+u@gmail.com> wrote:
>>>
>>>> I just about always use NULL, not 0, when I want a null pointer
>>>> constant.  Similarly, I use '\0', not 0, when I want a null
>>>> character, 0.0 when I want a floating-point zero, and false when I
>>>> want a Boolean zero.  I just like being explicit.
>>>
>>> Pointer:  I very rarely use NULL.
>>> Character:  I never use '\0'.
>>> Floating point:  I never use 0.0.
>>
>> Never say never!
>>
>>   printf("%f\n", 0);   // undefined behavior.
>>   printf("%f\n", 0.0); // correct
>
> Yes, but that's extremely rare that I want constant (except string
> literal) as variable argument to printf().
>
>> If you're #define-ing a floating-point constant that has
>> no fractional part, you should put that .0 there.
>
> I am trying hard to avoid #define-ing floating-point constants.
> In rare cases where it is not avoidable, most often the constant does
> have fractional part.  I am not sure what I would prefer when I can't
> avoid #define-ing and the constant has no fractional part.  Will I write
> something like '#define ANSWER ((double)42)' or (42.0) ?
> It depends on the mood of the minute.

Normally I would leave off the final 0 and just write 42.

Alternatively, a floating-point 42 can be written 42e0,
which stands out a little more than just using a trailing
dot.