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Is it possible to assign numeric value to an enum in Java?

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java

enums

People also ask

Can enums be assigned numerical values?

Can one assign custom numeric values to enum elements in Java? Not directly as you've written, i.e., where an enum value equals a number, but yes indirectly as shown in Ben S's link.

How do I assign a number to an enum?

If values are not assigned to enum members, then the compiler will assign integer values to each member starting with zero by default. The first member of an enum will be 0, and the value of each successive enum member is increased by 1. You can assign different values to enum member.

Can enum have numbers in Java?

No, we can have only strings as elements in an enumeration. Using strings in it, generates a compile time error.

Can we assign values to enum in Java?

You cannot create an object of an enum explicitly so, you need to add a parameterized constructor to initialize the value(s). The initialization should be done only once. Therefore, the constructor must be declared private or default. To returns the values of the constants using an instance method(getter).


public enum EXIT_CODE {
    A(104), B(203);

    private int numVal;

    EXIT_CODE(int numVal) {
        this.numVal = numVal;
    }

    public int getNumVal() {
        return numVal;
    }
}

Yes, and then some, example from documentation:

public enum Planet {
    MERCURY (3.303e+23, 2.4397e6),
    VENUS   (4.869e+24, 6.0518e6),
    EARTH   (5.976e+24, 6.37814e6),
    MARS    (6.421e+23, 3.3972e6),
    JUPITER (1.9e+27,   7.1492e7),
    SATURN  (5.688e+26, 6.0268e7),
    URANUS  (8.686e+25, 2.5559e7),
    NEPTUNE (1.024e+26, 2.4746e7);

    // in kilograms
    private final double mass;
    // in meters
    private final double radius;
    Planet(double mass, double radius) {
        this.mass = mass;
        this.radius = radius;
    }
    private double mass() { return mass; }
    private double radius() { return radius; }

    // universal gravitational 
    // constant  (m3 kg-1 s-2)
    public static final double G = 6.67300E-11;

    double surfaceGravity() {
        return G * mass / (radius * radius);
    }
    double surfaceWeight(double otherMass) {
        return otherMass * surfaceGravity();
    }
    public static void main(String[] args) {
        if (args.length != 1) {
            System.err.println("Usage: java Planet <earth_weight>");
            System.exit(-1);
        }
        double earthWeight = Double.parseDouble(args[0]);
        double mass = earthWeight/EARTH.surfaceGravity();
        for (Planet p : Planet.values())
           System.out.printf("Your weight on %s is %f%n",
                             p, p.surfaceWeight(mass));
    }
}

Assuming that EXIT_CODE is referring to System . exit ( exit_code ) then you could do

enum ExitCode
{
      NORMAL_SHUTDOWN ( 0 ) , EMERGENCY_SHUTDOWN ( 10 ) , OUT_OF_MEMORY ( 20 ) , WHATEVER ( 30 ) ;

      private int value ;

      ExitCode ( int value )
      {
           this . value = value ;
      }

      public void exit ( )
      {
            System . exit ( value ) ;
      }
}

Then you can put the following at appropriate spots in your code

ExitCode . NORMAL_SHUTDOWN . exit ( ) '


Extending Bhesh Gurung's answer for assigning values, you can add explicit method to set value

   public ExitCode setValue( int value){
      //  A(104), B(203);
      switch(value){
        case 104: return ExitCode.A;
        case 203: return ExitCode.B;
        default:
                   return ExitCode.Unknown //Keep an default or error enum handy
      }
   }

From calling application

int i = 104; 
ExitCode serverExitCode = ExitCode.setValue(i);

//You've valid enum from now

[Unable to comment to his answer, hence posting it separately]