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));
}
}