The leap year is February 29, not December 32 due to a Roman calendar quirk

Post by SamBam » Wed, Feb 28, 2024, 2:53 PM UTC

sebastialonso wrote: post #27

throw0101c wrote: post #6

Funny story about the year 2000 that does not involve Y2K: "Everyone" knows that leap years occur on year divisible by 4 ('first rule'). The second rule to them is that if a year is divisible by 100 (1800, 1900, …2000), then it is not a leap year. So a lot of folks did not have their systems/software have February 29 in the year 2000. But there is a third rule: if the year is divisible by 400 (like 1600… and 2000) it…

Wow the way this is presented is super confusing, to the point that your description includes a contradiction. Specifically, of a year is divisible by 400 it's also divisible by 100, so it's both a leap year and not leap year! Instead of showing rules as a linear list, I'd suggest it's easier to visualise it as a tree, or simpler still, as a series of nested ifs.

Post by PopAlongKid » Wed, Feb 28, 2024, 3:02 PM UTC

throw0101c wrote: post #29

sebastialonso wrote: post #27

Earlier quoted context omitted.

Wow the way this is presented is super confusing, to the point that your description includes a contradiction. Specifically, of a year is divisible by 400 it's also divisible by 100, so it's both a leap year and not leap year! Instead of showing rules as a linear list, I'd suggest it's easier to visualise it as a tree, or simpler still, as a series of nested ifs.

> Instead of showing rules as a linear list, I'd suggest it's easier to visualise it as a tree, or simpler still, as a series of nested ifs. Feel free to post a comment with ASCII art or (pseudo-)code. :)

   if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0)
      [it's a leap year]
   else
      [it's not]

Post by PopAlongKid » Wed, Feb 28, 2024, 3:13 PM UTC

throw0101c wrote: post #6

Funny story about the year 2000 that does not involve Y2K: "Everyone" knows that leap years occur on year divisible by 4 ('first rule'). The second rule to them is that if a year is divisible by 100 (1800, 1900, …2000), then it is not a leap year. So a lot of folks did not have their systems/software have February 29 in the year 2000. But there is a third rule: if the year is divisible by 400 (like 1600… and 2000) it…

Post by dave4420 » Wed, Feb 28, 2024, 3:15 PM UTC

roland35 wrote: post #13

foolswisdom wrote: post #11

Earlier quoted context omitted.

What? 13*28=364 So, missing ~1.25 days every year (instead of ~0.25 days each year with a 365 day calendar). How does this solve leap years?

1 or 2 "year day" holidays at the end of the calendar which aren't part of any month

Post by delecti » Wed, Feb 28, 2024, 3:24 PM UTC

PopAlongKid wrote: post #35

throw0101c wrote: post #6

Funny story about the year 2000 that does not involve Y2K: "Everyone" knows that leap years occur on year divisible by 4 ('first rule'). The second rule to them is that if a year is divisible by 100 (1800, 1900, …2000), then it is not a leap year. So a lot of folks did not have their systems/software have February 29 in the year 2000. But there is a third rule: if the year is divisible by 400 (like 1600… and 2000) it…

>Everyone" knows that leap years occur on year divisible by 4 ('first rule'). Actually, I think that's the only rule most people know. I think the "funny story" is actually the opposite: most people were treating 2000 as an ordinary every-4-year leap year, did not know about the 100 divisor, but were inadvertently saved by the 400 divisor. The Wikipedia link does document some cases of what you say (yes on the 2nd ru…