mead@uxh.cso.uiuc.edu (04/07/90)
Sorry if you caught this in another group (but then why did you look at
this one?).
I am writing a simulation in which the user will get (simulated)
"memos". These memos will have embedded symbols which my code shall
have to expand into appropriate dates (eg, @d3 might get expanded to
the string, 'Tuesday April 3, 1990' - the date three days before I'm
writing this note. Tomorrow, it would be expanded to 'Wednesday April
4, 1990', ...).
QUERY: Does anyone know of *any* source for an intelligent algorythm
for getting the day ('Monday, Tuesday, ...') from the date (4/3/90).
My PC does it like lightning each time I issue the 'DATE' command, and
if IBM can do it, anyone can - right? :) Textbooks or whatever are
fine, but please don't direct me to existing software unless it's PD
source code (in BASIC, C, Pascal, or FORTRAN). Thanks.
-alan mead : mead@uxh.cso.uiuc.edumouse@vaxb.acs.unt.edu (Dhanapong Saengrussamee, University of North Texas) (04/07/90)
In article <19500060@uxh.cso.uiuc.edu>, mead@uxh.cso.uiuc.edu writes: > QUERY: Does anyone know of *any* source for an intelligent algorythm > for getting the day ('Monday, Tuesday, ...') from the date (4/3/90). > My PC does it like lightning each time I issue the 'DATE' command, and > if IBM can do it, anyone can - right? :) Textbooks or whatever are > fine, but please don't direct me to existing software unless it's PD > source code (in BASIC, C, Pascal, or FORTRAN). Thanks. > > -alan mead : mead@uxh.cso.uiuc.edu I assume that the program you try to write is for PC, right? DOS interrupt $21 function $2A is what you need. Call with AH = $2A Return: CX = year (1980 through 2099--don't know what will happen after the year 2099 8^)) DH = month (1 through 12) DL = day (1 through 31) AL = day of week (0 = Sunday, 1 = Monday) Hope this help, Mouse .o()~ -----------------------------------+------------------------------------------ Dhanapong "Mouse" Saengrussamee | AppleLink : U1364 | BITNET : mouse@untvax Technical Support, CECS Dept., | BIX : d.mouse.s | CompuServe : 71301,1516 University of North Texas, | GENie : d.saengrussa | IP : 129.120.1.4 PO Box 5155, Denton, TX 76203-5155 | Internet : mouse@vaxb.acs.unt.edu voice (871) 565-4379 | SPAN : utspan::utandx::ntvaxb::mouse fax (817) 565-4425 | THENet : ntvaxb::mouse ------------------- UUCP : {...!uunet!convex!iex}!ntvax!vaxb.acs.unt.edu!mouse
scjones@sdrc.UUCP (Larry Jones) (04/08/90)
In article <19500060@uxh.cso.uiuc.edu>, mead@uxh.cso.uiuc.edu writes: > QUERY: Does anyone know of *any* source for an intelligent algorythm > for getting the day ('Monday, Tuesday, ...') from the date (4/3/90). > My PC does it like lightning each time I issue the 'DATE' command, and > if IBM can do it, anyone can - right? :) Textbooks or whatever are > fine, but please don't direct me to existing software unless it's PD > source code (in BASIC, C, Pascal, or FORTRAN). Thanks. The traditional algorithm is (in C): weekday = (year + year/4 + startday[month-1] + day) % 7; if (year%4 == 0 && month < 3) --weekday; year is either the full year or the last two digits, month is the month (1 - 12), and day is the day of the month (1 - 31). startday is a table of the day of the week each month starts on (in a non-leap year). Start by looking at a calendar and using the day of the week each month starts on (0=Sunday, 7=Saturday). Then, try an example and adjust all the table entries to get the correct result. (For example, if the date you try is a Tuesday (2) and the equation gives you Friday (6), then you need to subtract 4 (6-2) from each entry in the table. If the result is negative, just add 7.) ---- Larry Jones UUCP: uunet!sdrc!scjones SDRC scjones@SDRC.UU.NET 2000 Eastman Dr. BIX: ltl Milford, OH 45150-2789 AT&T: (513) 576-2070 "You know how Einstein got bad grades as a kid? Well MINE are even WORSE!" -Calvin