包含抽象方法的枚举类 学习笔记（二）

public enum Operation {PLUS{public double eval(double x,double y){return x+y;}},MINUS{public double eval(double x,double y){return x-y;}},TIMES{public double eval(double x,double y){return x*y;}},DIVIDE{public double eval(double x,double y){return x/y;}};//为枚举类定义一个抽象方法，这个抽象方法由不同的枚举值提供不同的实现。public abstract double eval(double x,double y);public static void main(String[] args){System.out.println(Operation.PLUS.eval(3,4));System.out.println(Operation.MINUS.eval(5,4));System.out.println(Operation.TIMES.eval(5,4));System.out.println(Operation.DIVIDE.eval(5,4));}}