Fridays the 13th, ported to Prime

[ggauny@live.fr]

(01-14-2015 09:16 PM)Tim Wessman Wrote:  I really need to get the days/date functions added...

Dear Sir,

I have tested my littles programs, all seem good running. So i give them to you.

For thoses who are interested in calendars calculations, there are very important
things to note :

1/ Calculations calendars are strictly from 1/1/-4712 up to 31/12/9999, after the precision goes down (dangerous when calculate astronomy or pursuit artificial satellites for example).

2/ Most importants programs are :
a/ D2JDc (DATE TO JULIAN DAY number, c stand for calcs only numericals),
ex : D2JDc(23.021951) return number 2,433,701. But
D2JD (23.021951) return one comment, if needed, like
"23.021951=2433701" not numeric

b/ JD2Dc (JULIAN DAY number TO DATE, c is the same signification)
ex : JD0Dc(2,433,701) return 23.021951, numeric date. But
JD2D (2,433,701) return a text comment like for example :
"Vendredi 23.021951 (JDN=2,433,701)

3/ To build a calendar, it is needed to know the day of the first month of a year,
FIRSTDAYOFYEARMOD give us the day of week, the date numeric and the
JDN of this day :

Ex : FIRSTDAYOFYEAR(2015) return :
"Jeudi 1.012015 (JDN = 2457024). I have subroutines by month yet.

I hope not have disturbed you.

My best regards.

Gérard. (i send you a big part of my programs, not calendar for any year because it is not possible to print, but i have always my 2 HP41, one C and the other CX).