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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