Enum

Enum:

  • It is introduce in Java 5.
  • it is a non-primitive data-type that is used to represent the set of constants such as week-days, months, directions etc.
  • It is by-default static and final .
  • It can be thought of as classes that have fixed set of constants.

 Features:

  • enum improves type safety.
  • enum can be easily used in switch.
  • enum can be traversed.
  • enum can have fields, constructors and methods.
  • enum may implement many interfaces but cannot extend any class because it internally extends Enum class.

Example:

 
class DemoEnum{

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

public static void main(String[] args) {
for (Directions val : Directions.values())
System.out.println(val);

}}
   
Output:
      NORTH
      SOUTH
      EAST
      WEST

values() method in enum:

values() method is internally added by java-compiler to enum.
It returns an array containing all the values of the enum.

Defining enum:

The enum can be defined within or outside the class because it is similar to a class.

Example of enum that is defined outside the class:
 
enum Directions { NORTH, SOUTH, EAST, WEST}

class EnumTest{
public static void main(String[] args) {

Directions val=Directions.EAST;
System.out.println(val);

}}
   
Output:
            EAST

Example ( within the class):


class EnumTest{
enum Directions { NORTH, SOUTH, EAST, WEST;}
//semicolon(;) is optional .

public static void main(String[] args) {
Directions val=Directions.SOUTH;
//enum type is required to access SOUTH
System.out.println(val);

}}
   
Output:SOUTH


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