Re: sizeof(x) / sizeof(x[0])

From	Keith Thompson <kst-u@mib.org>
Newsgroups	comp.lang.c
Subject	Re: sizeof(x) / sizeof(x[0])
Date	2017-01-14 16:01 -0800
Organization	None to speak of
Message-ID	<lnziitgpib.fsf@kst-u.example.com> (permalink)
References	<1420cd8f-e5cb-4a8f-93e6-d80a8b050650@googlegroups.com> <o5dkc2$gf1$1@dont-email.me>

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James Kuyper <jameskuyper@verizon.net> writes:
[...]
>      char segmented_string[] = "abc\0defg\0hijklmop\0";
>
> The array segmented_string contains all four of the strings that the
> elements of your "array" pointed at, starting at segmented_string,
> segmented_string+4, segmented_string+9, and segmented_string+18,
> respectively. The expression "sizeof segmented_string" has a value of
> 19, which is the total length of those strings, including their
> terminating null characters. That array also contains 15 other strings,
> such as "bc", which starts at segmented_string+1, and "p", which starts
> at segmented_string+16.

True, but I'd place a different emphasis.

The "length" of a string by definition excludes the terminating null
character (which is part of the string but does not contribute to its
"length").

`sizeof segmented_string` does happen to be "the total length of those
strings, including their terminating null characters", but it's simpler
and more correct to say that it's the size of the array object,
regardless of its contents.  For example, if you had written:

    char segmented_string[42] = "abc\0defg\0hijklmop\0";

then `sizeof segmented_string` would be 42.

-- 
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"

Thread

sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-14 04:16 -0800
  Re: sizeof(x) / sizeof(x[0]) "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-14 04:27 -0800
    Re: sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-14 04:43 -0800
      Re: sizeof(x) / sizeof(x[0]) "Fernando D. Bozzo" <fdbozzo@gmail.com> - 2017-01-14 04:52 -0800
        Re: sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-14 06:10 -0800
        Re: sizeof(x) / sizeof(x[0]) Keith Thompson <kst-u@mib.org> - 2017-01-14 15:55 -0800
  Re: sizeof(x) / sizeof(x[0]) jt@toerring.de (Jens Thoms Toerring) - 2017-01-14 13:13 +0000
    Re: sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-15 22:23 -0800
      Re: sizeof(x) / sizeof(x[0]) Keith Thompson <kst-u@mib.org> - 2017-01-16 08:58 -0800
  Re: sizeof(x) / sizeof(x[0]) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-14 14:47 +0000
    Re: sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-14 07:17 -0800
  Re: sizeof(x) / sizeof(x[0]) Manfred <noname@invalid.add> - 2017-01-14 16:22 +0100
  Re: sizeof(x) / sizeof(x[0]) Barry Schwarz <schwarzb@dqel.com> - 2017-01-14 08:35 -0800
    Re: sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-15 22:53 -0800
      Re: sizeof(x) / sizeof(x[0]) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-16 15:58 +0000
        Re: sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-16 22:38 -0800
          Re: sizeof(x) / sizeof(x[0]) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-17 10:11 +0000
  Re: sizeof(x) / sizeof(x[0]) James Kuyper <jameskuyper@verizon.net> - 2017-01-14 11:43 -0500
    Re: sizeof(x) / sizeof(x[0]) Keith Thompson <kst-u@mib.org> - 2017-01-14 16:01 -0800
    Re: sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-16 01:36 -0800
      Re: sizeof(x) / sizeof(x[0]) Barry Schwarz <schwarzb@dqel.com> - 2017-01-16 09:47 -0800
      Re: sizeof(x) / sizeof(x[0]) James Kuyper <jameskuyper@verizon.net> - 2017-01-16 21:12 -0500
        Re: sizeof(x) / sizeof(x[0]) Alla _ <modelling.data@gmail.com> - 2017-01-16 22:29 -0800
  Re: sizeof(x) / sizeof(x[0]) Les Cargill <lcargill99@comcast.com> - 2017-01-14 14:27 -0600
  Re: sizeof(x) / sizeof(x[0]) Keith Thompson <kst-u@mib.org> - 2017-01-14 15:52 -0800
  Re: sizeof(x) / sizeof(x[0]) Lőrinczy Zsigmond <nospam@for.me> - 2017-01-15 20:20 +0100
    Re: sizeof(x) / sizeof(x[0]) Keith Thompson <kst-u@mib.org> - 2017-01-15 12:55 -0800

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