Enumeration

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Enumeration
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Enumerated Data Types

• Can define a new simple type by listing
  (enumerating) the literal values
• enum ColorType RED, YELLOW, BLUE
• typedef int ColorType
• const int RED 0
• const int YELLOW 1
• const int BLUE 2

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Syntax

• Enum Declaration
• enum ltNamegt Enumerator, Enumerator,
• Assignment
• Identifier ConstIntExpression
• enum AnimalType RODENT, CAT, DOG, BIRD,
  REPTILE, HORSE, SHEEP
• AnimalType myPet DOG
• AnimalType yourPet RODENT
• yourPet myPet // Valid
• yourPet BIRD // Valid
• yourPet 3 // Invalid

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Example

• Why Boolean is not an enumerated type
• enum Boolean FALSE, TRUE
• Boolean isGreater
• float a, b
• isGreater (a gt b) //Invalid

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Operations on Enumerated Types

• I/O
• is only defined for the basic built-in
  typesint, float, char, not for enumerated types
• Incrementation
• myPet // Invalid
• myPet AnimalType(myPet 1) // Valid
• Comparison
• determined by their order in their declared
  enumeration

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Anonymous Data Types

• A type that does not have an associated
  identifier
• enum DOG, CAT, BIRD myPet
• enum DOG, CAT, BIRD yourPet
• yourPet myPet // Invalid