If you represent a set of boolean values as bits in a larger word, you’ll notice that each flag can be represented by a value that is a power of two.
- Singing = Bit 0 = 0 0 0 1 = 1
- Dancing = Bit 1 = 0 0 1 0 = 2
- Juggling = Bit 2 = 0 1 0 0 = 4
- Joke-Telling = Bit 3 = 1 0 0 0 = 8
You can use an enum type to represent these flags.
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| [Flags]public enum Talents { Singing = 1, Dancing = 2, Juggling = 4, JokeTelling = 8}; |
We can use a variable of type Talents to represent either a single talent:
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| Talents sinatra = Talents.Singing; // 1Talents wcFields = Talents.Juggling; // 4 |
Or we can represent a set of talents using a bitwise OR operator:
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| Talents fredTalents = Talents.Singing | Talents.Dancing; // 1 + 2 = 3Talents ernieTalents = Talents.Singing | Talents.Juggling | Talents.JokeTelling; // 1 + 4 + 8 = 13 |
The Flags attribute indicates that this enum type can be used to store a set of flags. Using a different bit for each flag means that we can store any combination of flags at the same time.