17) DAY OF WEEK (457 B)
To use: LOAD 6, RUN 500

500 REM
510 REM DAY OF WEEK
520 REM
530 LET D$="   SUNMONTUEWEDTHUFRISAT"
540 PRINT "ENTER DATE:"
550 PRINT "DAY",
560 INPUT D
570 IF D<1 OR D>31 THEN GOTO 560
580 PRINT D
590 PRINT "MONTH",
600 INPUT M
610 IF M<1 OR M>12 THEN GOTO 600
620 PRINT M
630 PRINT "YEAR",
640 INPUT Y
650 IF Y<1700 THEN GOTO 640
660 PRINT Y
670 LET K=0
680 IF M=1 OR M=2 THEN LET K=1
690 LET L=Y-K
700 LET O=M+12*K
710 LET P=L/100
720 LET Z=(13*(O+1))/5+(5*L)/4-P+P/4+D-1
730 LET Z=Z-7*(Z/7)+1
740 FOR I=1 TO Z*3
750 LET D$=TL$(D$)
760 NEXT I
770 PRINT "IT IS ";CHR$(CODE+(D$));
780 LET D$=TL$(D$)
790 PRINT CHR$(CODE(D$));CHR$(CODE(TL$(D$)))
800 PRINT
810 PRINT "AGAIN? (Y)"
820 INPUT A$
830 CLS
840 IF CODE(A$)=62 THEN GOTO 530
850 STOP