!	PROGRAM : DATE - This calculates the day of the week from a given
!			month, day, and year
!	AUTHOR	: Bob Livesay; Data Pulse, Inc.
!		We got this code out of a book of handy subroutines.
!		I don't like its use of simplistic data names but it
!		seems to work so I decided not to mess with it.
!		NOTE: It is up to you to verify the validity of the
!		date and the year must really be 4 digits.
!------------------------------------------------------------------------

map1	DAY(7),				S,	9
map1	MONTH'TABLE(12)
	map2	MONTH'DAYS,		B,	1
	map2	MONTH'CODE,		B,	1
	map2	MONTH,			S,	9

	DAY(1)="Sunday"    :  DAY(2)="Monday"   :  DAY(3)="Tuesday"
		DAY(4)="Wednesday" :  DAY(5)="Thursday" :  DAY(6)="Friday"
		DAY(7)="Saturday"
	MONTH'DAYS(1)=31  :  MONTH'CODE(1)=0 : MONTH(1)="January"
		MONTH'DAYS(2)=28  :  MONTH'CODE(2)=3  :  MONTH(2)="February"
		MONTH'DAYS(3)=31  :  MONTH'CODE(3)=3  :  MONTH(3)="March"
		MONTH'DAYS(4)=30  :  MONTH'CODE(4)=6  :  MONTH(4)="April"
		MONTH'DAYS(5)=31  :  MONTH'CODE(5)=1  :  MONTH(5)="May"
		MONTH'DAYS(6)=30  :  MONTH'CODE(6)=4  :  MONTH(6)="June"
		MONTH'DAYS(7)=31  :  MONTH'CODE(7)=6  :  MONTH(7)="July"
		MONTH'DAYS(8)=31  :  MONTH'CODE(8)=2  :  MONTH(8)="August"
		MONTH'DAYS(9)=30  :  MONTH'CODE(9)=5  :  MONTH(9)="September"
		MONTH'DAYS(10)=31 :  MONTH'CODE(10)=0 :  MONTH(10)="October"
		MONTH'DAYS(11)=30 :  MONTH'CODE(11)=3 :  MONTH(11)="November"
		MONTH'DAYS(12)=31 :  MONTH'CODE(12)=5 :  MONTH(12)="December"

START'JOB:
	MO=2  : DA=27 : YR=1987
	gosub	GET'DAY
	?tab(-1,0); "When the date is "; MONTH(MO); " "; 	&
		DA using "#Z"; ", "; YR using "####"; "    ";	&
		"The day is "; DAY(DAY'OF'WEEK)
	end

GET'DAY:
	I1=int((YR-1500)/100)
	A=I1*5+(I1+3)/4
	I2=int(A-int(A/7)*7)
	Y2=int(YR/100)
	Y3=int(YR-Y2*100)
	A=Y3/4+Y3+DA+MONTH'CODE(MO)+I2
	DAY'OF'WEEK=int(A-int(A/7)*7)+1
	if  MO>2  goto  WRAPUP'DATE
	if  Y3=0  then  A=I1-1					:&
		T1=int(A-int(A/4)*4)				:&
		if  T1=0  then  DAY'OF'WEEK=DAY'OF'WEEK-1	:&
			goto	WRAPUP'DATE
	T1=int(YR-int(YR/4)*4)
	if  T1<>0  goto  WRAPUP'DATE
	if DAY'OF'WEEK=0  then  DAY'OF'WEEK=6
	DAY'OF'WEEK=DAY'OF'WEEK-1
WRAPUP'DATE:
	if DAY'OF'WEEK=0  then  DAY'OF'WEEK=7
	return