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


Groups > comp.lang.c > #69227

Re: Program to compute amount of coins

From Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups comp.lang.c
Subject Re: Program to compute amount of coins
Date 2015-09-03 23:07 +0100
Organization A noiseless patient Spider
Message-ID <87lhcnf97k.fsf@bsb.me.uk> (permalink)
References (4 earlier) <msa1e1$9oq$1@node2.news.atman.pl> <878u8ngti7.fsf@bsb.me.uk> <msaajf$iof$1@node2.news.atman.pl> <87wpw7fcpv.fsf@bsb.me.uk> <msaej7$msp$1@node2.news.atman.pl>

Show all headers | View raw


bartekltg <bartekltg@gmail.com> writes:

> On 03.09.2015 22:51, Ben Bacarisse wrote:
>> bartekltg <bartekltg@gmail.com> writes:
<snip>
> It looks like you think about this much more than I did.

!!

Not necessarily more, just differently.  As an ex-teacher, I see
exercises as micro-problems used to illustrate things that become
important in bigger systems.  It's fine to work up a solution and move
on, but I am used to trying to prepare model solutions to exercises that
will be scrutinised by dozens of enquiring minds, year after year.  It
gave me a mind set of studying every line for best practise.

It probably comes over as hyper-critical -- I'm sorry about that.  I
don't mean it to be negative, just as another perspective.

<snip>
>>> Or hardcode array length.
>>> But your version is safer.
>>>      const int N = 5;
>>>      int coin_value[N]= {25, 10, 5,1};
>>> do not generates a error or warning,
>>> and the last entry is uninitialized.
>>
>> And that's a "variable length array" in C (it isn't in C++) and these
>> (much to my dismay) has been made optional in C11.
>
> Are you sure this is the problem?

That VLAs are now optional?  I don't really know how much of a problem
it will be in practice, but it's an odd precedent.  I'm no longer sure
what C11 features I can reply on arriving in due course.  Maybe some of
them will be optional in C19 (or whatever).

> I compiled it in c++ with
> -Wall -Wpedantic -Wextra -std=c++98
> (so no variable length arrays) and it still work and do not generate
> any warnings.
> N is const.

Yes, C++ does not have VLAs.  This is an area where the same source code
has different meanings between C and C++.  C90 (or a C11) conforming
compiler could reject the code, but a C++ compiler must accept it.

-- 
Ben.

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


Thread

Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-03 08:54 -0700
  Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-03 17:07 +0100
    Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-03 10:02 -0700
    Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-03 10:12 -0700
    Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-03 10:18 -0700
      Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-03 18:30 +0100
        Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-03 19:53 +0200
          Re: Program to compute amount of coins Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-03 21:03 +0100
            Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-03 22:29 +0200
              Re: Program to compute amount of coins Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-03 21:51 +0100
                Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-03 23:37 +0200
                Re: Program to compute amount of coins Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-03 23:07 +0100
                Re: Program to compute amount of coins James Kuyper <jameskuyper@verizon.net> - 2015-09-03 18:24 -0400
                Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-04 00:30 +0200
                Re: Program to compute amount of coins Keith Thompson <kst-u@mib.org> - 2015-09-03 16:36 -0700
                Re: Program to compute amount of coins Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 14:00 -0700
              Re: Program to compute amount of coins Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 13:58 -0700
                Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-07 05:07 +0200
                Re: Program to compute amount of coins Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-07 13:14 +0100
                Re: Program to compute amount of coins Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-08 02:39 -0700
                Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-08 18:29 +0200
                Re: Program to compute amount of coins James Kuyper <jameskuyper@verizon.net> - 2015-09-08 13:15 -0400
                Re: Program to compute amount of coins Keith Thompson <kst-u@mib.org> - 2015-09-08 10:16 -0700
          Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-04 04:09 -0700
            Re: Program to compute amount of coins Bartc <bc@freeuk.com> - 2015-09-04 12:16 +0100
            Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-04 14:11 +0200
          Re: Program to compute amount of coins Ike Naar <ike@iceland.freeshell.org> - 2015-09-04 19:06 +0000
            Re: Program to compute amount of coins James Kuyper <jameskuyper@verizon.net> - 2015-09-04 15:12 -0400
            Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-05 01:54 +0200
              Re: Program to compute amount of coins Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-09-05 01:01 +0100
                Re: Program to compute amount of coins bartekltg <bartek@gmail.com> - 2015-09-05 02:50 +0200
  Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-03 18:09 +0200
    Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-03 17:11 +0100
      Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-03 18:38 +0200
    Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-03 10:08 -0700
      Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-03 18:20 +0100
      Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-03 19:32 +0200
    Re: Program to compute amount of coins Keith Thompson <kst-u@mib.org> - 2015-09-03 12:18 -0700
  Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-03 10:16 -0700
    Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-03 18:24 +0100
      Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-03 10:37 -0700
        Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-03 19:02 +0100
  Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-03 10:42 -0700
    Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-03 19:57 +0200
    Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-03 19:05 +0100
  Re: Program to compute amount of coins Bartc <bc@freeuk.com> - 2015-09-03 21:23 +0100
    Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-03 21:55 +0100
    Re: Program to compute amount of coins Keith Thompson <kst-u@mib.org> - 2015-09-03 16:39 -0700
      Re: Program to compute amount of coins Tim Rentsch <txr@alumni.caltech.edu> - 2015-09-06 14:02 -0700
        Re: Program to compute amount of coins Keith Thompson <kst-u@mib.org> - 2015-09-06 17:04 -0700
  Re: Program to compute amount of coins Alla _ <modelling.data@gmail.com> - 2015-09-04 03:48 -0700
    Re: Program to compute amount of coins bartekltg <bartekltg@gmail.com> - 2015-09-04 14:04 +0200
    Re: Program to compute amount of coins Richard Heathfield <rjh@cpax.org.uk> - 2015-09-04 14:23 +0100

csiph-web