[boost] Re: [boost] [gacap]Is any interesting to "Generating All Combinations and Permutations"£¿

From: Ben Bear (benbearchen_at_[hidden])
Date: 2007-11-13 01:50:13

2007/11/13, Hervé Brönnimann <hervebronnimann_at_[hidden]>:
> Ben:  the naming partial_permutation would be a very good idea.  I
> like it.  Am I correct that your (very cute!) idea would be extended
> to prev_ as follows:
>
> bool next_partial_permutation(first, middle, last)
> {
>    reverse (middle, last);
>    return next_permutation(first, last);
> }
>
> prev_partial_permutation (
> {
>    bool result = next_permutation(first, last);

oh,  here should be:-)
      bool result = prev_permutation(first, last);

>    reverse (middle, last);
>    return result;
> }
>
> That's all good, then.  BTW, you *should* assume that the client has
> already sorted the range.  In other words, garbage in, garbage out,
> and that's OK.  There's not reason to penalize those who keep their
> ranges sorted.  It simply needs to be documented as a Requirement:
> and given again as a Post-condition: (since the functions maintain
> the sorted range invariant).
>

ok, I will prepare a resume source code that contains
partial_permutation and combination, but without initializatons.  It
will be very simple, against gacap.