题解 | #判断学生成绩等级#

import java.util.Scanner;
import java.util.HashMap;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String grade = scanner.next();

        //write your code here......
        // System.out.print("A".equals(grade) ? "优秀" : "B".equals(grade)
        //                 ? "良好" : "C".equals(grade)
        //                 ? "及格" : "D".equals(grade)
        //                 ? "不及格" : "未知等级");

        // String str=null;
        // switch(grade){
        //     case "A":str="优秀"; break;
        //     case "B":str="良好"; break;
        //     case "C":str="及格"; break;
        //     case "D":str="不及格"; break;
        //     default:str="未知等级"; break;
        // }
        // System.out.print(str);

        HashMap<String, String> map = new HashMap<>();
        map.put("A", "优秀");
        map.put("B", "良好");
        map.put("C", "及格");
        map.put("D", "不及格");
        System.out.print(map.keySet().contains(grade) ? map.get(grade) : "未知等级");
    }
}