RED(3), ORANGE(10), YELLOW(21), GREEN(5), BLUE(1), INDIGO(-1), VIOLET(-11);

    private final int value;

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

    public int getValue() { return value; }

}

​

public class prog {

    public static void main(String[] args) {

        System.out.println(Rainbow.YELLOW.ordinal());

    }

}