Day of Week Calendar

   1 REM "CALENDAR1"
  10 PRINT "ENTER YEAR"
  20 INPUT Y
  30 IF Y<1900 OR Y>1999 THEN GOTO 20
  40 PRINT "ENTER MONTH(JAN=1 TO DEC=12)"
  50 INPUT M
  60 PRINT "NOW ENTER DATE"
  70 INPUT D
  80 LET A$="SUNMONTUEWEDTHUFRISAT"
  90 LET Y$=STR$ Y
 100 LET T=VAL Y$(3 TO 4)
 110 LET T=INT (T+T/4)
 120 IF M=1 OR M=10 THEN LET T=T+1
 130 IF M=2 OR M=3 OR M=11 THEN LET T=T+4
 140 IF M=5 THEN LET T=T+2
 150 IF M=6 THEN LET T=T+5
 160 IF M=8 THEN LET T=T+3
 170 IF M=9 OR M=12 THEN LET T=T+6
 180 IF Y<>1900 AND Y/4-INT (Y/4)=0 AND (M=1 OR M=2) THEN LET T=T+1
 190 LET T=T+D
 200 LET T=T-7
 210 IF T<=0 THEN GOTO 230
 220 GOTO 200
 230 LET T=T+7
 240 PRINT D;"/";M;"/";Y;" IS/WAS ON A ";(A$(T*3-2 TO T*3))
 250 STOP 
 260 SAVE "1017%8"
 270 RUN