980508-1 Specify an ASN.1 data type to indicate for all days of the year, whether each day was a holiday or a working day. Only these two values are allowed.

Answer
alternative 1:

DaysOpen ::= BIT STRING (SIZE (365..366))

Answer
alternative 2:

DaysOpen ::= SEQUENCE SIZE (12) OF
                   MonthDaysOpen

MonthDaysOpen ::= BIT STRING (SIZE (28..31))

Answer
alternative 3:

Year ::= SEQUENCE SIZE (365..366) OF
             IsWorkingDay

IsWorkingDay ::= BOOLEAN

Common
error 1:

A common error was to use a CHOICE, but have the same tag on both the data types in the tag. This is not permitted, CHOICE requires different tag for all alternatives in a CHOICE.

Common
error 2:

Another common error was to use SEQUENCE instead of SEQUENCE OF. (Or SET instead of SET OF.)

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