Re: SORTA

["John McKay" <jmckay@xxxxxxxxxxxxxxxx>]

Barbara,

   Thanks first of all for taking the time to give a detailed reply to my 
proposed solution.

   The "solution would work for the exact data " because that is all I had 
to work with and it was an answer to his question.  It is now up to Dave to 
implement the solution (if he so desires) adjusting it to suit his 
particular circumstances.  In  answering questions on these forums, my 
approach is to try not to read too much background from the question, rather 
answer the question closely and let others adapt to suit.

  While your solution is  more robust,  Barbara, I would point out that 
%subarr() was introduced in V5R3 - not all shops have migrated, even at this 
stage.

Regards,
John McKay
www.mckaysoftware.ie
www.rpglanguage.com

----- Original Message ----- 
From: "Barbara Morris" <bmorris@xxxxxxxxxx>
To: <rpg400-l@xxxxxxxxxxxx>
Sent: Friday, November 14, 2008 5:51 PM
Subject: Re: SORTA


> John McKay wrote:
> > As far as I can see, the code in  the answer does not add the values
> > together.
> > ...
> > C specs
> >     sorta acc;
> >     for x = 1 to 3;
> >       y = *zeros;
> >       z = x  + 1;
> >       y = %lookup(acc(x): acc: z);
> >       if y > *zeros;
> >         sum$(x) += sum$(y);
> >         sum$(y) = *zeros;
> >         acc(y) = *blanks;
> >       endif;
> >     endfor;
>
> John, I think your solution would work for the exact data that David
> showed, but I don't think it would work if there were more than two
> values the same.  Say the acc values were A B B B, then it would add
> sum(3) to sum(2), but it should also add sum(4) to sum(2).
>
> But also, I don't think it would work more than once, since it would
> have blank "unused" acc values that would get sorted to the beginning of
> the array.
>
> Here's my attempt at a solution, completely untested ...
>
> Since the number of "real" elements in the array is not fixed (starts
> with 4 elements, ends up with 3 elements), we need a variable to keep
> track, say num_elems.
>
>    // sort the array by acc.  If there is more than one element
>    // for any one acc, they will now be together in the array
>    sorta %subarr(acc : 1 : num_elems);
>
>    // merge the sum values for elements with the same acc value
>    i = 1;
>    remove_elems = 0;
>    dow i < num_elems;
>       // loop through the subsequent elements with the same
>       // acc value, and add all the sums to sum(i)
>       for j = (i + 1) to num_elems;
>          if acc(j) = acc(i);
>             sum(i) += sum(j);
>             // now that sum(j) is added to sum(i)
>             // we want to get rid of element j
>             // (but just mark it to be removed later)
>             acc(j) = *hival;
>             remove_elems += 1;
>          else;
>             // we have a new acc
>             leave;
>          endif;
>          // continue with the element after the
>          // last one we merged
>          i = j;
>       endfor;
>    enddo;
>
>    // re-sort the array to put the discarded ones
>    // at the end (they were set to *hival),
>    // then adjust the number of actual elements
>    sorta %subarr(acc : 1 : num_elems);
>    num_elems -= remove_elems;
>
> --
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