100 REM Long year
110 DECLARE EXTERNAL FUNCTION IsLY
120 DECLARE EXTERNAL FUNCTION WD
130 PRINT "****     List of ISO long years     ****"
140 INPUT PROMPT "Start year: ": S
150 INPUT PROMPT "End year: ": E
160 PRINT
170 FOR Y = S TO E
180    IF IsLY(Y) <> 0 THEN PRINT Y;
190 NEXT Y
200 PRINT
210 END
220 REM
230 EXTERNAL FUNCTION IsLY(Y)
240 REM Nonzero if Y is long
250 IF (4 = WD(Y)) OR (3 = WD(Y - 1)) THEN
260    LET IsLY = -1
270 ELSE
280    LET IsLY = 0
290 END IF
300 END FUNCTION
310 REM
320 EXTERNAL FUNCTION WD(Y)
330 LET WD = MOD(Y + INT(Y / 4) - INT(Y / 100) + INT(Y / 400), 7)
340 END FUNCTION