Re: Konvalina/Wileman exercises

Richard Heathfield wrote:
>
.... snip ...
> 
> Another six are up now for peer review:
> 
> http://www.cpax.org.uk/prg/****table/pascal/pwp/exercises/ch04/index.php
> 
> #1 is ugly, no two ways about it. I was determined to use loops,
> even when it meant coming up with the most truly abysmal customised
> hash I've ever seen.
> 
> The race-track one (#4) threw me for a while, before I realised I
> could chuck the car's mass away - it turns out to be irrelevant to
> the problem.
> 
> The last one - the trig thing - is probably the flakiest. I'm not
> too hot on these array things - Pascal's handling of arrays is a
> bit bizarre to my mind.

In general you are too exacting.  Look at the problem for a quick
solution, and you will usually find it.  This doesn't mean there
are false solutions.  Remember you can set the base index for an
array, and use that.  Having your own readinteger routine is handy,
and easy with f^ and get.  Having a global set variable holding
digits is also useful.  Remember that f^ gives you an advance look
at the input char (or any other char).

I find the polynomial solution a horror.  For example, a poly can
be calculated as:

int poly(x : int; coeffs : array[*] of int) : int;
 
   begin
   p = 1; i = coeff[0];
   repeat
     p := p * x + coeff[i]; i = pred(i);
   until i = 0;
   return p;
   end;

which isn't strictly accurate, because the size of the array is
variable.

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