FULLSCREEN CONTENTS Project Home Page
.TOPIC.......: Fdate's Leap Year Algorithm
.ALIAS.......: lyalgol
.DISCUSSION..:
Here is how Fdate decides whether or not a year is a leap year.


Using this algorithm:

See "A Machine Algorithm for Processing Calendar Dates", by Henry F. Fliegel (Georgetown University Observatory) and Thomas C. Van Flandern (U.S. Naval Observatory) COMMUNICATIONS OF THE ACM, Volume 11, Number 10, October 1968

There is supposedly a new adjustment to the leapyear algorithm, which specifies the additional exception:

EXCEPT THAT
Every year evenly divisible by 4000 IS a leap year

See "Bit By Bit" column, COMPUTER LANGUAGE, November 1989, p. 148. This adjustment is not part of Fdate's leapyear algorithm. Unless your application is working with dates 2,000 years in the future, the lack of this exception will be irrelevant for you.