Enums – constant specific functionality

• public enum Operation { PLUS, MINUS, TIMES, DIVIDE;

• // Do arithmetic op represented by this constant

• • double eval(double x, double y){
  • • switch(this) {
    • • case PLUS: return x + y;
      • case MINUS: return x - y;
      • case TIMES: return x * y;
      • case DIVIDE: return x / y;
    • }
  • throw new AssertionError("Unknown op: " + this);
  • }

• }