Question

Suppose there is an ENUM

enum Operations { 
  ADD, 
  SUBTRACT, 
  MULTIPLY
}

I want to use this enum to add two numbers(say 5 and 3) and get the output as 8
or
I want to use this enum to subtract two numbers(say 9 and 3) and get the output as 6

Question:

• is this possible?
• if yes than what are the modifications to be done to this enum?

Answer 1

enums can have abstract methods, and each member can implement it differently.

enum Operations {
  ADD {
    public double apply(double a, double b) { return a + b; }
  }, 
  SUBTRACT {
    public double apply(double a, double b) { return a - b; }
  }, 
  MULTIPLY {
    public double apply(double a, double b) { return a * b; }
  }, 
  ;

  public abstract double apply(double a, double b);
}

will allow you to do

Operations op = ...;
double result = op.apply(3, 5);