On Sat, 16 Nov 2013, Reinier Olislagers wrote:
On 16/11/2013 18:21, Michael Van Canneyt wrote:
On Fri, 15 Nov 2013, Bart wrote:
The fun part for me is the fact that a seemingly simple question,
where at first glance you would think "I'll just implement that", can
lead to so many "problems".
I added a modified version of your implementation to the DateUtils unit as:
Procedure PeriodBetween(Const ANow, AThen: TDateTime; Out Years, months,
days : Word);
I chose this name because it is more in line with the existing
XXXBetween functions.
I did change the algorithm so it does not do the correction for february
of the leap year.
It returns now the same results as the Jedi function. (which I didn't
take for license reasons)
Thanks for providing an implementation.
A suggestion if I may: given the wide variation of possibilities of
interpretation, some comments in the code about how the calculation is
supposed to work would be very much appreciated, I'm sure.
(Of course, that applies even more to added documentation).
Just wanted to avoid another huge thread discussing PeriodBetween in
future... as well as confusion on the part of possible users in general.
When documenting, all will be explained.
I think it's fairly simple, really.
Start with D1. Call this D.
Keep adding 1 to year of D till your jumps over D2.
If you jumped over, substract 1 from year.
Keep adding 1 to month of D till D jumps over D2.
If you jumped over, substract 1 from month.
Keep adding 1 to day of D till D reaches D2.
The number of years, months, days you thus added is the period.
I may fiddle a bit with the definition of "jumps over" and "reaches", but essentially that is it.
Michael.
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