Determine Day of Week in RPG

[Guest.Visitor]

Anyone know of an easy way to determine the day of week given a date in YYYYMMDD format? TIA, Chuck Ackerman

[B.Myrick]

Chuck, Use the SEARCH facility at the top of the forum screen. Look for: "Day of Week". This produced 50 hits. There are some good examples there. -bret

[Guest.Visitor]

Search the www for Zeller's Congruence; No kidding... it can be coded easily even in RPG. I tested it against rexx dates over the 400 year cycle of the Gregorian calendar and it proved correct. It's also referred to by W. F. Schindler in his book. bobh

[Guest.Visitor]

Determine a base date that you know the weekday of (Jan 1, 2000 is a Sat), use the SUBDUR opcode to find the number of days difference, divide by 7 and use the remainder with 0=Sat, 1=Sun....

[Guest.Visitor]

That's good, if you know the DOWK for 01 Jan of every year and the day number of the date in question. bobh

[D.Handy]

John, "...and use the remainder with 0=Sat, 1=Sun..." And don't forget to first check if the remainder < zero, and if so, to add 7. This simple addition handles the cases where the request date is prior to the base date. Doug PS - Do you really want 0=Saturday? That seems unusual. Choose your base date to get the desired day to be a remainder of zero.

[Guest.Visitor]

Hi, I solved this as follows. Write a CLP with these statements in it : CRTDTAARA DTAARA(&RTNLIB/TSBDAYNAME) TYPE(*CHAR) + LEN(15) TEXT('BACKUP : Temporary dataarea + for retrieval dayname') STRREXPRC SRCMBR(TSBDAYNAME) SRCFILE(&RTNLIB/TSBREXX) Then write a REXX-proc. with this in it : /************************************************** ****************/ /* Program-id : TSBDAYNAME */ /* Written by : Rob Baartwijk */ /* Description : Retrieve name of current day, store it in */ /* DTAARA TSBDAYNAM. */ /************************************************** ****************/ ARG RTNPARM RTNPARM=DATE('W') 'CHGDTAARA TSBDAYNAME' RTNPARM After the rexx-procedure has run you will find the name of the day in the dataarea(e.g. MONDAY, TUESDAY, etc.) No more calculations, no more startdates, no more exceptions ! HTH, Rob.

[David Abramowitz]

Search on CEEDAYS. There are three "CEE" APIs that are specifically designed for this purpose. Dave

[Guest.Visitor]

Rob, Even simpler (for your requirement) which is different to Chuck's : RTVSYSVAL QDAYOFWEEK David

[Guest.Visitor]

But David, that's cheating !!!!!! LOL! This systemvalue is not present on every version of OS/400 I believe. So I just came up with an alternative programming-approach. But of course, if someone is really looking for a solution, yours is the easiest/newest/simplest. G'Day, Rob.