100'  NAME--CALENDAR
110'
120'  DESCRIPTION--DETERMINES THE DAY OF THE WEEK ON WHICH A
130'  GIVEN DATE FALLS.
140'
150'  SOURCE--UNKNOWN
160'
170'  INSTRUCTIONS--TYPE "RUN" AND FOLLOW INSTRUCTIONS.
180'
190'
200'  *  *  *  *  *  *  *   MAIN PROGRAM   *  *  *  *  *  *  *  *  *
210'
220 PRINT "THIS PROGRAM DETERMINES THE DAY OF THE WEEK"
230 PRINT "ON WHICH A GIVEN DATE FALLS."
240   DIM F(12), L(12)
250 MAT READ F
260   DATA  0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5
270 MAT READ L
280  DATA 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
290 GOTO 960
300  IF Y < 1 THEN 470
310  IF M > 12 THEN 470
320  IF M < 1 THEN 470
330  IF D < 1 THEN 470
340  IF Y > 1752 THEN 540
350  IF Y < 1582 THEN 490
360  IF Y = 1752 THEN 430
370  IF Y = 1582 THEN 390
380  GO TO 510
390  IF M < 10 THEN 490
400  IF M > 10 THEN 510
410  IF D < 15 THEN 490
420  GO TO  510
430  IF M < 9 THEN 510
440  IF M > 9 THEN 540
450  IF D < 14 THEN 510
460  GO TO 540
470  PRINT "UNACCEPTABLE DATA -- TRY AGAIN."
480 GOTO 970
490  LET G1 = 0
500  GO TO  520
510  LET G1 = 1
520  LET J1 = 1
530  GO TO 560
540  LET G1 = 1
550  LET J1 = 0
560  IF J1 <> 1 THEN 740
570  LET L1 = 0
580  LET A = Y + INT((Y+3)/4)
590  IF Y <> INT(Y/4)*4 THEN 640
600  LET L1 = 1
610  IF M < 3 THEN 640
620  LET L = 1
630  GO TO 650
640  LET L = 0
650  LET Z = A + D + L + F(M) + 5
660  LET Z = Z - INT(Z/7)*7
670  LET Q = L(M)
680  IF M <> 2 THEN 700
690  LET Q = Q + L1
700  IF D > Q THEN 470
710 PRINT "OLD STYLE CALENDAR:  ";
720 LET W=1
730  GOSUB 1110
740 IF G1<>1 THEN 970
750  LET L1 = 0
760  LET Y = Y - 400*INT(Y/400)
770  LET A = Y + INT((Y+3)/4) - INT((Y-1)/100)
780  IF Y <> INT(Y/4)*4 THEN 850
790  IF Y = 0 THEN 810
800  IF Y = 100*INT(Y/100) THEN 850
810  LET L1 = 1
820  IF M < 3 THEN 850
830  LET L = 1
840  GO TO 860
850  LET L =0
860  LET Z = A + D + L + F(M)
870  LET Z = Z - INT(Z/7)*7
880  LET Q = L(M)
890  IF M <> 2 THEN 910
900  LET Q = Q + L1
910  IF D > Q THEN 470
920 IF W=0 THEN 940
930 PRINT "NEW STYLE CALENDAR:  ";
940 GOSUB 1110
950 GOTO 970
960 PRINT "ENTER MONTH NUMBER, DATE, AND YEAR."
970 PRINT
980 IF W1=0 THEN 1060
990 PRINT "IS THERE ANOTHER DATE YOU WANT TO KNOW";
1000 MAT INPUT A$
1010 IF A$(1)="NO" THEN 1260
1020 IF A$(1)="YES" THEN 1050
1030 PRINT "INCORRECT ANSWER.  PLEASE TYPE 'YES' OR 'NO'."
1040 GOTO 1000
1050 PRINT
1060 PRINT "ENTER DATE:  ";
1070 LET W=0
1080 LET W1=1
1090  INPUT M, D, Y
1100  GO TO 300
1110 ON Z+1 THEN 1120,1140,1160,1180,1200,1220,1240
1120  PRINT "FRIDAY"
1130 RETURN
1140  PRINT "SATURDAY"
1150  RETURN
1160  PRINT "SUNDAY"
1170  RETURN
1180  PRINT "MONDAY"
1190  RETURN
1200  PRINT "TUESDAY"
1210  RETURN
1220  PRINT "WEDNESDAY"
1230  RETURN
1240  PRINT "THURSDAY"
1250  RETURN
1260 END