Consider these classes:
考虑这些类:
struct OrderedSet<T: Hashable> {}
class Exercise: Hashable {}
class StrengthExercise: Exercise {}
class CardioExercise: Exercise {}
struct OrderConsider these classes:
考虑这些类:
struct OrderedSet<T: Hashable> {}
class Exercise: Hashable {}
class StrengthExercise: Exercise {}
class CardioExercise: Exercise {}
struct Order