📅  最后修改于: 2022-03-11 14:52:49.342000             🧑  作者: Mango
public sealed class NumberSystem
// The permits clause has been omitted
// as all the subclasses exists in the same file.
{ }
final class Binary extends NumberSystem { .. }
final class Octal extends NumberSystem { .. }
final class HexaDecimal extends NumberSystem { .. }
sealed class Decimal extends NumberSystem { .. }
final class NonRecurringDecimal extends Decimal {..}
final class RecurringDecimal extends Decimal {..}