What day of week is this???

[Guest.Visitor]

It is absolutely amazing how many times this situationoccurs in DP. Next to the DOLLAR SIGN, dates are the most important datum in any business function. If you have ROBOT it has a day of week function. If youcan find it, there is an API for it, but I have never looked... The one I use is in the 1934 edition of Websters New collegiate Dictionary ;; by the way it works through2299 and is under perpetual calendar; It goes as follows: 1. take the last two figures of the year (e.g. 97) and add the integer(yy/7) (no decimal fraction); 2. for the current century add 0; for the next century, add 6.3 for the months add: 0 for april or july; 1 for jan or oct; 2 for May; 3 for aug; 4 for feb mar or nov; 5 for june; 6 for sept or dec; if a leap year use instead 0 for jan & 3 for feb.4. add the day of month;5 divide the result by 7 and the remainder will represent the DOW: with 0 = sat; 1 = sun etc. I have programmed this algorithm in assembler, algol, cobol and RPG and I know of a version in Auto-coder, C and PASCAL. Incidently ;; january 1st, 2000 will be Saturday; check it out.this means monday jan 3rd , 2000 will be a holiday so we will nothave to worry about 2 digit year stuff until tuesday! bob hamilton, texas business systems; 736 pinehurst; richardson, texphone 817-898-6770 off; 972-705-9214 home... No One Ever Needed a Smaller, Slower PC

[flensburg@novasol.dk]

Hi Kendall, Date-handling capabilities are not limited to V3R2 but to RPG/IV. - so if you have the ILE RPG compiler, calculating the duration between two dates and in terms the day of week is straight forward. About the OPNQRYF-approach; I noticed that Ted Holt published the technique in Tech Talk January 1996. Please let me know if you need further information (I've got an RPG/400-inline (6/8-digits date) that works very well too). Best regards, Carsten

[flensburg@novasol.dk]

Hi Kendall, Date-handling capabilities are not limited to V3R2 but to RPG/IV. - so if you have the ILE RPG compiler, calculating the duration between two dates and in terms the day of week is straight forward. About the OPNQRYF-approach; I noticed that Ted Holt published the technique in MC Tech Talk January 1996. Please let me know if you need further information (I've got an RPG/400-inline (6/8-digits date) that works very well too). Best regards, Carsten

[Guest.Visitor]

Bob: I tried to get the day of the week using your formula for March 26, 1997 which is Wednesday. 97/7 = 13 without decimals. 97 + 13 + 0 + 4(march) + 26 = 140 140 mod 7 = 0 = Saturday. Did I miss something ? Regards, HREF="http://www2.cybernex.net/~irash/">Ira On Sunday, March 23, 1997, 09:19 AM, bob hamilton wrote: 1. take the last two figures of the year (e.g. 97) and add the integer(yy/7) (no decimal fraction); 2. for the current century add 0; for the next century, add 6. 3 for the months add: 0 for april or july; 1 for jan or oct; 2 for May; 3 for aug; 4 for feb mar or nov; 5 for june; 6 for sept or dec; if a leap year use instead 0 for jan & 3 for feb. 4. add the day of month; 5 divide the result by 7 and the remainder will represent the DOW: with 0 = sat; 1 = sun etc.

[Guest.Visitor]

the DOW formula is in ALGOL for ccYYMMDD case( MOD( YY + mod(YY, 4) + ( case cc = 19 then 0; cc = 20 then 1 + mm + dd ) ,7 ) = 0 then "Saturday"; OR = 1 then "Sunday"; et c ) . the case statement give s the correction for century nbr. i dont haveat hand the nbr for 17th and 18th centruy, but 19 is 0) No One Ever Needed a Smaller, Slower PC

[Guest.Visitor]

I don't get Bob's formula either Today is Thursday Nov 6 1997. 97/7 = 13 97+13=110 110+0=110 (for current century) . 110+4=114 (for november) . 114+6=120 (for day in month) . 120/7 = 17 rem 1. 1=SUN, not Thursday.... Bob?.Chris Ringer....

[Guest.Visitor]

Bob E-mailed me and explained that in the first step, you should divide by 4 not 7. Thanks Bob. Chris Ringer...

[Guest.Visitor]

On Tuesday, November 25, 1997, 12:24 PM, Chris Ringer wrote: Bob E-mailed me and explained that in the first step, you should divide by 4 not 7. Thanks Bob. Chris Ringer...

---

from the formula can you tell why this year's calendar is identical to that for 1941??? Bob Hamilton TEXAS BUSINESS SYSTEMS 736 Pinehurst Richardson, Texas 75080