Enum in java.

enum in java

• It is a collection of named constant.
• It is declared with enum keywrod.
• Each enumeration constant is public, static and final by default.
• constant value can't be changed once it is defined.
• It is also called user defined data type.
• Value of enum should be in uppercase letters but not compulsory.
• new keyword is not used to create variable of enum.
• We can access the value of enum by using dot(.) operator.
• Syntax of enum

 enum enum_name
  {
   value 1,value 2,value 3,.....,value n
  }

• Example

enum Languange 
  {
    C,
    JAVA,
    PHP,
    ANDROID
  } 
class Program 
{
  public static void main(String[] args) 
  {
   /*creating variable of enum*/
    Languange myVar = Languange.ANDROID; 
    System.out.println(myVar);
  }
}
/*
Output
ANDROID
*/

• Example:Enum within class

 class Program 
{
  enum Languange 
  {
    C,
    JAVA,
    PHP,
    ANDROID
  }
  public static void main(String[] args) 
  {
   /*creating variable of enum*/
    Languange myVar = Languange.ANDROID; 
    System.out.println(myVar);
  }
}
/*
Output
ANDROID
*/

• Example:Enum with switch

enum Languange 
  {
    C,
    JAVA,
    PHP,
    ANDROID
  } 
class Program 
{
  public static void main(String[] args) 
  {
   /*creating variable of enum*/
    Languange myVar = Languange.JAVA; 
    switch(myVar)
    {
      case C:
      System.out.println("Fees:"+3500);
      break;
      case JAVA:
      System.out.println("Fees:"+6000); 
      break; 
      case PHP:
      System.out.println("Fees:"+8000); 
      break;
      case ANDROID:
      System.out.println("Fees:"+10000); 
      break;
    }
  }
}
/*
Output
Fees:6000
*/

• Example:Enum with constructor
• enum have also a constructor like class but enum constructor is called separately for each constant value of enum.

enum Languange 
  {
    /*enum constants value*/
    C,JAVA, PHP, ANDROID;
    /*enum constructor*/
    /*Note:enum constructor is
    called separately for each constant
    */
    private Languange()
    {
        System.out.println("called for: "+this.toString());
    }
  } 
class Program 
{
  public static void main(String[] args) 
  {
   /*creating variable of enum*/
    Languange myVar = Languange.JAVA; 
    System.out.println(myVar);
  }
}
/*
Output
called for: C
called for: JAVA
called for: PHP
called for: ANDROID
JAVA
*/

• Example:Enum with function
• we can also define function inside enum like a normal function and we can call it by using enum variable and dot(.) operator.

enum Languange 
  {
    /*enum constants value*/
    C,JAVA, PHP, ANDROID;
    /*Defining function inside enum*/
    public void fun()
    {
        System.out.println("called for: "+this.toString());
    }
  } 
class Program 
{
  public static void main(String[] args) 
  {
   /*creating variable of enum*/
    Languange myVar = Languange.JAVA;
   /*calling function*/
    myVar.fun();
  }
}
/*
Output
called for: JAVA
*/