import java.util.ArrayList;
import java.util.Scanner;

// 学生成绩实体
class Student {
    String id;
    String name;
    int score;

    public Student(String id, String name, int score) {
        this.id = id;
        this.name = name;
        this.score = score;
    }
}

public class ScoreManager {
    static ArrayList<Student> list = new ArrayList<>();
    static Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        while (true) {
            System.out.println("====成绩管理系统====");
            System.out.println("1.添加成绩 2.查询全部 3.按学号查找 4.修改成绩 5.删除 0.退出");
            System.out.print("请输入选项：");
            int op = sc.nextInt();
            sc.nextLine();

            switch (op) {
                case 1: add(); break;
                case 2: showAll(); break;
                case 3: findById(); break;
                case 4: update(); break;
                case 5: delete(); break;
                case 0: System.out.println("退出");return;
                default:System.out.println("输入错误");
            }
        }
    }

    static void add(){
        System.out.print("学号：");String id=sc.nextLine();
        System.out.print("姓名：");String name=sc.nextLine();
        System.out.print("分数：");int s=sc.nextInt();sc.nextLine();
        list.add(new Student(id,name,s));
        System.out.println("添加成功");
    }

    static void showAll(){
        for(Student s:list){
            System.out.println(s.id+"\t"+s.name+"\t"+s.score);
        }
    }

    static void findById(){
        System.out.print("输入学号：");String id=sc.nextLine();
        for(Student s:list){
            if(s.id.equals(id)){
                System.out.println(s.id+"\t"+s.name+"\t"+s.score);
                return;
            }
        }
        System.out.println("未找到");
    }

    static void update(){
        System.out.print("学号：");String id=sc.nextLine();
        for(Student s:list){
            if(s.id.equals(id)){
                System.out.print("新分数：");
                s.score=sc.nextInt();sc.nextLine();
                System.out.println("修改完成");
                return;
            }
        }
        System.out.println("找不到学生");
    }

    static void delete(){
        System.out.print("学号：");String id=sc.nextLine();
        for(int i=0;i<list.size();i++){
            if(list.get(i).id.equals(id)){
                list.remove(i);
                System.out.println("删除成功");
                return;
            }
        }
        System.out.println("不存在");
    }
}