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");
        }
    }