SUB ValidateOption (Choice$, Min, Max, Flag)
REM This subroutine will ensure that the OPTION selcted was valid. IF it IS valid
REM Flag = 0, IF NOT Flag = 1
PRINT
SELECT CASE INT(VAL(Choice$))
    CASE IS > Max
        Flag = 1
        PRINT "Sorry, but the value you have entered is far too big"
        PRINT "Please choose again between"; Min; "and"; Max
    CASE IS < Min
        Flag = 1
        PRINT "Sorry, but the value you have entered is far too small"
        PRINT "Please choose again between"; Min; "and"; Max
    CASE IS > Min AND < Max
        Flag = 0
    CASE ELSE
        Flag = 1
        PRINT "Please choose a number between"; Min; "and"; Max
END SELECT
END SUB