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Re: Application Exercises

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Ben Bacarisse <ben.usenet@bsb.me.uk> writes:

> ram@zedat.fu-berlin.de (Stefan Ram) writes:
>
>>   Disclaimer:  I might have posted about the same programming
>>   problem some years ago.  But then it was my own invention,
>>   while now I read about it in a book.
>>
>>   In a book about the job application as a programmer, I found
>>   a paragraph, were they say that application exercises often
>>   enforce arbitrary restrictions, which do not make sense
>>   according to the author of this book, but the exercises have
>>   to be done nevertheless.  As an example he gave:
>>
>> |Write a function to detect whether two integral numbers are
>> |equal without using any comparison operators.
>>
>>   . As a hint he wrote:  "Think of bit operators.".
>
> I think that's a bad hint.  It points towards thinking about
> representations and not values, which looks to me to be the rockier
> road.
>
> I'm thinking along these lines:
>
>  #define CMP(a, b) !((unsigned)(a) - (unsigned)(b))
>
>  CMP(a/2, b/2) && CMP(a - a/2, b - b/2)

An interesting (and nice!) idea.  How about

    CMP(a/5, b/5) && CMP(a%5, b%5)

instead?  (The choice of 5 is arbitrary, except that I
wanted to be well away from the boundary of the bad
ranges.)  Using the / and % I find it easier to convince
myself it's correct.

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Re: Application Exercises Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-04-06 23:46 +0100
  Re: Application Exercises Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-04-07 00:08 -0700
    Re: Application Exercises Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-04-08 01:24 +0100

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