Enums

Enumeration (enum) is a special user defined type where we specify a set of values for a variable and the variable can only take one out of a small set of possible values. Enumerations are classified as a reference data type.

The keyword enum is used to define an enumeration.

An enum can contain constants, methods, etc.

Syntax

Here’s the basic syntax for creating an enum:

public enum name {
  constant1,
  constant2,
  ...
}

Here’s an enum with compass directions:

public enum Direction {
  NORTH, SOUTH, EAST, WEST
}

• Direction.NORTH will have a value of 0.
• Direction.SOUTH will have a value of 1.
• Direction.EAST will have a value of 2.
• Direction.WEST will have a value of 3.

Example

public enum Day {
  SUN, MON, TUE, WED,
  THU, FRI, SAT
}

• Day.SUN will have a value of 0.
• Day.MON will have a value of 1.
• Day.TUE will have a value of 2.
• Day.WED will have a value of 3.
• Day.THU will have a value of 4.
• Day.FRI will have a value of 5.
• Day.SAT will have a value of 6.

To access one of the values:

Day day = Day.MON;