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From: Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups: comp.programming
Subject: Re: A little puzzle.
Date: Tue, 22 Nov 2022 12:53:42 +0000
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Richard Heathfield <rjh@cpax.org.uk> writes:

> On 21/11/2022 8:45 pm, Ben Bacarisse wrote:
>> I wonder if there are any real posters here?
>
> Nobody here but us chickens.
>
>>  Let's see...
>> I came across a trivial programming task that must have been solved a
>> thousand times by other programmers, but it had never crossed my path
>> until yesterday.  I must be feeling my age because I made a real hash of
>> tackling it at first.  Anyway, I thought it might be of interest.
>> Consider any ordered measure that "wraps round" -- bearings in degrees,
>> minutes in the hour, indeed hours in either the 12 or 24 hour clock.
>> The problem is to determine if a given value is in the sub-range
>> specified by a start and an en value.
>> I was specifically concerned with integer values where the sub-range
>> includes the start value but excludes the end value.
>> Though I am not sure this merits the term "puzzle", I suggest that
>> solutions be posted with some spoiler protection.  Do all the news
>> readers used by programmers (or ex programmers) all respect the presence
>> of a form-feed character...
>
> Dunno. Let's find out:
>
> Ctrl-L coming up:
>
>
>

Didn't see a form feed there.  Here's one (I hope):



> although of course in C the problem would be far better solved as:
>
> int inrange(int lo, int hi, int k)
> {
>   return (lo <= k) && (k < hi);
> }
>
> or even as a macro.
>
> I must confess I'm not entirely certain I have correctly interpreted
> your puzzle, which I have taken to mean "is this a given value in the
> given range", but this seems just a bit too easy for you to make a
> hash of, but I'm sure I've made hashes of worse. I've missed
> something, haven't I?

The circular wrapping.  On a clock, 55 is in the range of minutes that
starts at 45 and ends at 5.

-- 
Ben.