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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: Pointers, constant values
Date: Fri, 16 Oct 2015 12:13:11 -0700
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Bartc <bc@freeuk.com> writes:
> On 16/10/2015 16:25, Keith Thompson wrote:
>> Alla _ <modelling.data@gmail.com> writes:
>> [...]
>>> int array_sum (int array[], const int n);
>>
>> One piece of advice:
>>
>> The parameter declaration
>>      int array[]
>> really means
>>      int *array
>>
>> There is no such thing as an array parameter in C, but it uses
>> array-like syntax to define pointer variables.
>>
>> My advice is *not* to take advantage of that special-case rule.  It's a
>> pointer, so define it as a pointer:
>>
>>      int array_sum (int *array, const int n);
>
>> Not everyone will agree with this; some will argue that using the []
>> notation is a reminder that it points to an element of an array, not
>> just a single int object.
>
> But 'int *array' *is* a pointer to a single element.

Yes.  Isn't that pretty much what I said?  It's a pointer to an int
object; using array notation suggests that that object is the initial
element of an array.  (Then again, for at least some purposes *any*
single object can be treated as an element of a 1-element array.)


>                                                      C allows you to
> pass a pointer to an actual array, if not the array itself:
>
>  int array_sum(int (*array)[], int n);

Yes, but there's not much you can do with it, since you haven't
specified the length of the array it points to.  (I'm a little surprised
that that declaration is legal.)

> However this also now requires proper array dereferencing and
> indexing, not just applying an offset to an arbitrary pointer which
> can be to anything:
>
>  (*array)[i]

That won't compile unless you have something between the [] in the
declaration.

-- 
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"