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From: Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups: comp.lang.c
Subject: Re: how cast works?
Date: Sun, 11 Aug 2024 20:37:08 -0700
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Bart <bc@freeuk.com> writes:

> On 12/08/2024 01:46, Tim Rentsch wrote:
>
>> Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
>>
>>> Bart <bc@freeuk.com> writes:
>>> [...]
>>>
>>>> Take:
>>>>
>>>>      int a; double x;
>>>>
>>>>      x = (double)a;
>>>>
>>>> The cast is implicit here but I've written it out to make it clear.
>>>
>>> [...]
>>>
>>> The *conversion* could be done implicitly, but you've used a cast (i.e.,
>>> an explicit conversion) to make it clear.
>>
>> The statement assigning to x performs two conversions:  an explicit
>> one caused by the cast, and an implicit one caused by the assignment
>> operation.
>
> The 'x' term is the other side of the cast from the 'a' term.
>
> So after '(double)a' has been evaluated, both sides of '=' have the
> type 'double', so no further conversion is needed.

The C standard requires that a conversion take place as part of
the assignment, even when the types are the same.

Furthermore, there are cases where having to do a conversion from
one type to the same type has semantic consequences, even though
the types are the same.