(41CX/DM41)(17Bii) Date of the first Advent Sunday in a year

02042020, 10:34 PM
(This post was last modified: 02042020 10:35 PM by jthole.)
Post: #1




(41CX/DM41)(17Bii) Date of the first Advent Sunday in a year
This small program is an adaptation of an equation I have in my HP 17Bii. One of the reasons for posting this here, is that it shows the elegance of the HP 17Bii solver. The other reason is that it's fun, and can be useful (if only because you know when to open the first window of the Advent calendar ;) ).
First of all, here is the short and simple HP 17Bii Solver equation: (both the solver and program assume DD.MMYYYY). Code:
And here is the HP 41CX/DM41L program, which takes the year in the X register (just following the equation; maybe could be optimised further). Code:
Running on the 17Bii: Enter YEAR: 2021 Solve ADVDATE: 28,112021 Running on the DM41L: 2021 XEQ ADVDATE 28,112021 Of course, the program (and equation) only works for the Gregorian calendar. Monday Jan. 1, 1900 was chosen because I liked that date (any date works, as long as you adjust the offset (currently 22) in the equation. BTW; I do not have a HP 41CX, but I do have a SwissMicros DM41L; I tested the program on the DM41L. 

08102020, 03:02 PM
(This post was last modified: 08102020 03:11 PM by ggauny@live.fr.)
Post: #2




RE: (41CX/DM41)(17Bii) Date of the first Advent Sunday in a year
Hi,
I see your thread a little late but here is a little routine of mine I was using with my HP 41c (+ time module) or my HP 41cx. Instead of DDays I'm using DOW, but unfortunatly DOW gives 0 if the day is a sunday, (HP Prime gives 7). So we have to "adjust" in case of DOW gives a 0. Code:
Of course runing on dm41, dm41x too and some other calculator. 2016 gives 27.112016 for example, 1582 gives 28.111582 In attachement I give 2 EXCEL calendars. May be usefull. Have a good day. Gérard. 

08112020, 08:03 AM
(This post was last modified: 08112020 02:29 PM by Werner.)
Post: #3




RE: (41CX/DM41)(17Bii) Date of the first Advent Sunday in a year
If you use 12.12 instead of 25.12, and change the 21 to 8, it will work for M.DY format as well.
[update] not quite.. but if you use 12.12, then do 13 DAYS+, then proceed as before, it will ;) [update #2] and if you take the first of January of the next year (which is always the same Day of Week as Christmas), it's even simpler: Code: 1 

01222021, 01:27 PM
Post: #4




RE: (41CX/DM41)(17Bii) Date of the first Advent Sunday in a year
(08102020 03:02 PM)ggauny@live.fr Wrote: Hi, For HP Prime: DATEADD((IP(Date)+.1225),(21+DAYOFWEEK(IP(Date)+0.1225))) for actual year SHIFT Define <function> for user defined function HP 33C 34C 11C 41CX 32S 28C HP71B 35s 50g Prime Rev. A, C, D. DM 41X, 42. TI 58C, 59, 74, 92II, Voyage 200, nspire CX IIT, Sanyo ICC 82D and more 

01242021, 05:00 AM
Post: #5




RE: (41CX/DM41)(17Bii) Date of the first Advent Sunday in a year
(08102020 03:02 PM)ggauny@live.fr Wrote: Instead of DDays I'm using DOW, but unfortunatly DOW gives 0 if the day is a sunday, (HP Prime gives 7). No need to adjust, just shift the reference to Christmas Eve. Better yet, reference to Dec 3, eliminated the need to subtract 21 days. 1st Advent Sunday = (Dec 3)  DOW(Dec 3) days // Nov 27 to Dec 3 Code below assumed date format MM.DDYYYY Code: 00 { 29Byte Prgm } Since DOW(Dec 3) = DOW(Dec 31), we can even do this in the head, using facts below: 1. Gregorian calendar repeat itself every 400 years. 2. DOW(Dec 31, 2000) = 0 (Sunday) 3. 365 days = 52 weeks + 1 day Example, Year 2016: 2016 % 400 = 16 leap years count = IP(16/4)  IP(16/100) = 4 DOW(Dec 31, 2016) = (4 + 16) % 7 = 6 (Dec 3, 2016)  6 days = Nov 27, 2016 Example, Year 2021: 2021 % 400 = 21 leap years count = IP(21/4)  IP(21/100) = 5 DOW(Dec 31, 2021) = (5 + 21) % 7 = 5 (Dec 3, 2021)  5 days = Nov 28, 2021 

01242021, 10:35 AM
Post: #6




RE: (41CX/DM41)(17Bii) Date of the first Advent Sunday in a year
Hi Albert,
Thank for the optimisation !!! Great. Gérard. 

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