(05-10-2017 01:33 PM)Don Shepherd Wrote: here is the one I have been using for many years, on many different platforms, and it is easy to implement and works well:

dbd algorithm

I do the first one (calculate day number from date) for both dates and subtract.

Unfortunately that is also as heavy (resources) as the JDN method. Heavy if the use case is only max.50 years in current century. Those gregorian leapyear corrections are unnecessary memory usage if one stays between 2000 and 2100 (what my current understanding is.).

Anyhow, someone else might have use of it.