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