Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #163259

Re: on the order of the const-keyword

Show all headers | View raw

Manfred <noname@add.invalid> writes:

> On 10/29/2021 6:30 PM, David Brown wrote:

>> In other words, it applies fine to the large majority of declarations.
>> You can add "inside out" to it to cover more cases.
>>
>> I understand that this is a simplification - but that's what people need
>> at the start.
>
> Not sure about that, at least not this kind of simplification.
> I think Bart made a good point, in noting that the right-to-left rule
> does not work well in some case, notably with pointers to arrays,
> which is something to be considered at any level of C knowledge.

The simple rule goes wrong for even simpler cases:

  int a[3][5];
  double f(double);

If you start at the name, the rule is to read to the right, and only
switch to reading left when you have to (which needs to be tied down).
This is because []s and ()s bind more tightly than *:

   int *a[10];
        >>>>>     "a is an array of 10"
   <<<<<          "pointers to int"

The reference to "inside out" means you need to finish off parentheses
before moving outside:

   int (*a)[10];
        <<          "a is a pointer to"
          >>>>>     "an array of 10"
    <<<<            "int"

Mind you, I don't usually do it this way.  I read the declarator (the
part that decorates the name) like I do expressions.  I don't vocalise

   *a[10]

in an expression like 

   *a[10] = 42

I know the precedence and associativity so I know this is indexing 'a' and
dereferencing the result, as opposed to

  (*a)[10] = 42

which dereferences a pointer and indexes the result.

-- 
Ben.

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

on the order of the const-keyword Meredith Montgomery <mmontgomery@levado.to> - 2021-10-28 12:50 -0300
  Re: on the order of the const-keyword Bart <bc@freeuk.com> - 2021-10-28 17:25 +0100
    Re: on the order of the const-keyword "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2021-10-28 10:10 -0700
      Re: on the order of the const-keyword Guillaume <message@bottle.org> - 2021-10-28 20:40 +0200
      Re: on the order of the const-keyword Meredith Montgomery <mmontgomery@levado.to> - 2021-10-29 00:07 -0300
        Re: on the order of the const-keyword James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-29 00:48 -0400
    Re: on the order of the const-keyword Thiago Adams <thiago.adams@gmail.com> - 2021-10-28 12:56 -0700
      Re: on the order of the const-keyword Thiago Adams <thiago.adams@gmail.com> - 2021-10-28 13:18 -0700
        Re: on the order of the const-keyword Bart <bc@freeuk.com> - 2021-10-28 21:35 +0100
          Re: on the order of the const-keyword Thiago Adams <thiago.adams@gmail.com> - 2021-10-28 13:57 -0700
            Re: on the order of the const-keyword Thiago Adams <thiago.adams@gmail.com> - 2021-10-28 14:07 -0700
              Re: on the order of the const-keyword Bart <bc@freeuk.com> - 2021-10-28 22:54 +0100
              Re: on the order of the const-keyword Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-28 15:37 -0700
                Re: on the order of the const-keyword Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-10-29 00:02 +0100
        Re: on the order of the const-keyword Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-10-28 22:10 +0100
        Re: on the order of the const-keyword Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-10-28 15:13 -0700
        Re: on the order of the const-keyword Meredith Montgomery <mmontgomery@levado.to> - 2021-10-29 00:40 -0300
    Re: on the order of the const-keyword Meredith Montgomery <mmontgomery@levado.to> - 2021-10-28 23:48 -0300
  Re: on the order of the const-keyword James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-10-28 13:04 -0400
    Re: on the order of the const-keyword Meredith Montgomery <mmontgomery@levado.to> - 2021-10-29 00:34 -0300
  Re: on the order of the const-keyword David Brown <david.brown@hesbynett.no> - 2021-10-29 10:03 +0200
    Re: on the order of the const-keyword Bart <bc@freeuk.com> - 2021-10-29 11:30 +0100
      Re: on the order of the const-keyword David Brown <david.brown@hesbynett.no> - 2021-10-29 16:31 +0200
        Re: on the order of the const-keyword Bart <bc@freeuk.com> - 2021-10-29 16:45 +0100
          Re: on the order of the const-keyword David Brown <david.brown@hesbynett.no> - 2021-10-29 18:30 +0200
            Re: on the order of the const-keyword Manfred <noname@add.invalid> - 2021-10-30 00:32 +0200
              Re: on the order of the const-keyword Meredith Montgomery <mmontgomery@levado.to> - 2021-10-29 20:03 -0300
              Re: on the order of the const-keyword Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-10-30 01:10 +0100
            Re: on the order of the const-keyword Bart <bc@freeuk.com> - 2021-10-29 23:51 +0100
    Re: on the order of the const-keyword Meredith Montgomery <mmontgomery@levado.to> - 2021-10-29 12:22 -0300
      Re: on the order of the const-keyword David Brown <david.brown@hesbynett.no> - 2021-10-29 18:34 +0200
        Re: on the order of the const-keyword Meredith Montgomery <mmontgomery@levado.to> - 2021-10-29 17:04 -0300

csiph-web