package geyao.item.data;

public class Student {
    private String id;
    private String name;
    private int age;
    private String address;

    public Student() {
    }

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

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

package geyao.item.data;

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

public class StudentSystem {
    public static void main(String[] args) {
        ArrayList<Student> list=new ArrayList<>();
        loop:while (true){
            System.out.println("---欢迎来到学生管理系统-----");
            System.out.println("1:添加学生");
            System.out.println("2:删除学生");
            System.out.println("3:修改学生");
            System.out.println("4:查询学生");
            System.out.println("5:退出学生");
            System.out.println("请输入你的选择");

            Scanner sc=new Scanner(System.in);
            String choose=sc.next();
            switch (choose){
                case "1"-> addStudent(list);
                case "2"-> deleteStudent(list);
                case "3"-> updateStudent(list);
                case "4"-> queryStudent(list);
                case "5"-> {
                    System.out.println(":退出");
                    //跳出当前循环
                    break loop;
                }
                default-> System.out.println("没有这个选项");
            }
        }


    }

    public static void addStudent(ArrayList<Student> list){
        System.out.println("添加学生");
        Student s=new Student();
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入学生的id");
        String id=sc.next();
        boolean flag=contains(list,id);
        while (true){
            if(flag){
                System.out.println("id已经存在 请重新录入");
            }else{
                //id不存在
                s.setId(id);
                break;
            }
        }
        System.out.println("请输入学生的姓名");
        String name=sc.next();
        s.setName(name);
        System.out.println("请输入学生的年龄");
        int age=sc.nextInt();
        s.setAge(age);
        System.out.println("请输入学生的的家庭住址");
        String address=sc.next();
        s.setAddress(address);

        list.add(s);
        System.out.println("学生信息添加成功");
    }

    public static void deleteStudent(ArrayList<Student> list){

        System.out.println("删除学生");
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入要删除得学生id");
        String id=sc.next();
        int index=getIndex(list,id);
        if(index>=0){
            list.remove(index);
            System.out.println("id为"+id+"的删除成功");
        }else {
            System.out.println("删除的id不存在");
        }
    }

    public static void updateStudent(ArrayList<Student> list){
        System.out.println("修改学生");
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入要修改得学生id");
        String id=sc.next();
        int index=getIndex(list,id);
        if(index==-1){
            System.out.println("要修改的id不存在");
            return;
        }
        Student stu=list.get(index);
        System.out.println("请输入要修改得学生姓名");
        String newName=sc.next();
        stu.setName(newName);

        System.out.println("请输入要修改得学生年龄");
        int newAge=sc.nextInt();
        stu.setAge(newAge);

        System.out.println("请输入要修改得学生地址");
        String newAddress=sc.next();
        stu.setAddress(newAddress);
        System.out.println("修改成功");
    }

    public static void queryStudent(ArrayList<Student> list){
        if(list.size()==0){
            System.out.println("当前无学生信息,请添加后再查询");
            return;
        }
        System.out.println("id\t\t姓名\t\t年龄\t\t家庭住址");
        //当代码执行到这里
        for (int i = 0; i < list.size(); i++) {
            Student stu=list.get(i);
            System.out.println(stu.getId()+"\t"+stu.getName()+"\t"+stu.getAge()+"\t"+stu.getAddress());
        }
    }
   //判断是否存在
    public static boolean contains(ArrayList<Student> list,String id){
//        for (int i = 0; i < list.size(); i++) {
//            Student stu=list.get(i);
//            String sid=stu.getId();
//            if(sid.equals(id)){
//                return true;
//            }
//        }
//        return  false;
        return getIndex(list,id)>=0;
    }
    //得到学生对象得id
    public static int getIndex(ArrayList<Student> list,String id){
        for (int i = 0; i < list.size(); i++) {
            Student stu=list.get(i);
            String sid=stu.getId();
            if(sid.equals(id)){
                return i;
            }
        }
        return  -1;
    }
}