//定义了4个等级

 enum Level{

     A，B，C，D

 }

 class Level{

     public static final Level A = new Level();

     public static final Level B = new Level();

     public static final Level C = new Level();

     public static final Level D = new Level();

 }

 enum Level{

     A("85~100","优"),

     B("75~84","良"),

     C("60~74","中"),

     D("60以下","差");

     private String score;

     private String ctype;

     private  Level(String score,String ctype){     //构造方法必须是私有的

         this.score = score ;

         this.ctype = ctype;

     }

     public String getscore(){

         return this.score;

     }

     public String getctpye(){

         return this.ctype;

     }

 }

 public class Enumation {

     public static void main(String[] args) {

         System.out.println(Level.A.getscore());

         System.out.println(Level.A.getctpye());

         Level[] ls = Level.values();

     }

 }

 //输出结果

 //85~100

 //优

 enum Level{

     A("85~100"){

         @Override

         public String getctpye() {

             return "优";

         }

     },

     B("75~84") {

         @Override

         public String getctpye() {

             return "良";

         }

     },

     C("60~74") {

         @Override

         public String getctpye() {

             return "中";

         }

     },

     D("60以下") {

         @Override

         public String getctpye() {

             return "差";

         }

     };

     private String score;

     private  Level(String score){

         this.score = score ;

     }

     public String getscore(){

         return this.score;

     }

     public abstract String getctpye();  //每个对象都要重写抽象方法

 }

 public class Enumation {

     public static void main(String[] args) {

         System.out.println(Level.C.name()); //返回枚举常量的名称

         System.out.println(Level.C.ordinal()); //返回枚举常量的序号（下标从0开始）

         Level[] ls = Level.values();        //遍历枚举类型

         for(Level l :ls){

             System.out.println(l);

         }

         String letter = "B" ;

         //返回带指定名称的指定枚举类型的枚举常量，若letter为非枚举类型会抛异常java.lang.IllegalArgumentException: No enum constant

         Level b = Level.valueOf(letter);

         System.out.println(b.B);

     }

 }