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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Program to compute amount of coins |
| Date | 2015-09-03 21:51 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <87wpw7fcpv.fsf@bsb.me.uk> (permalink) |
| References | (2 earlier) <e3fbe659-268a-4a19-8aa5-a9c4bdf76438@googlegroups.com> <Ns%Fx.510855$JH3.131464@fx37.am4> <msa1e1$9oq$1@node2.news.atman.pl> <878u8ngti7.fsf@bsb.me.uk> <msaajf$iof$1@node2.news.atman.pl> |
bartekltg <bartekltg@gmail.com> writes:
> On 03.09.2015 22:03, Ben Bacarisse wrote:
>> bartekltg <bartekltg@gmail.com> writes:
>> <snip>
>>> I'm sure that these loops teacher mentioned was a loop over "face
>>> value".
>>
>> Yes, that must surely be it.
>>
>>> #include <stdio.h>
>>> #include <math.h>
>>>
>>> int main(void)
>>> {
>>> double amount;
>>> const unsigned int coin_value[]= {25,10, 5,1 } ;
>>>
>>> printf ("Please, enter your amount in $: \n");
>>>
>>> if (scanf("%lf", &amount) == 1)
>>> {
>>> if (amount > pow(2.0,32.0)*0.9999){
>>
>> That's an odd number to test against. For 32-bit unsigned ints things
>> go wrong for values < 0 and >= pow(2, 32)/100.
>
> Yes.
> I was thinking about 0.00999. Probably:)
Ah, right. Mind you, that's still odder than just dividing by the
multiplier you are going to use later (100), and the difference (2**32 x
0.00001) still over 42,949. Not that that really matters here since
it's an exercise, but there is serious point to be made: it's good to
avoid things that make the reader think more than they need to. I'd
have to ask myself why 0.00999? Is is safe? It is too conservative?
Does that matter? And so on.
<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.
--
Ben.
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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
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