using System;   

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Student tester = new Student();

        Student addMember = new Student(3 ,"Hà", "Ha Noi","0913456", 19, "Phòng ban cntt");

        List<Student> testers = new List<Student>(){

            new Student(1 ,"Giang", "Ha Noi","0913456", 20, "Phòng ban cntt"),

            new Student(2 ,"Hoàng", "Ha Noi","0913456", 21, "Phòng ban cntt")

        };

        tester.GetStudents(testers);

        Console.WriteLine("----------Sau Khi add-----------");

        tester.GetStudents(tester.AddStudent(testers, addMember));

    }

}

public class People {

    public int Id { get; set; }

    public string Name { get; set; }

    public string Address { get; set; }

    public string Phone { get; set;}

    public int Age { get; set; }

    public People() {}

    public People(int Id ,string Name, string Address,

                  string Phone, int Age){

        this.Id = Id;

        this.Name = Name;

        this.Address = Address;

        this.Phone = Phone;

        this.Age = Age;

    }

}

public class Student : People {

    public string Department { get; set; }

    public Student(){}

    public Student(int Id, string Name, string Address, string Phone, int Age, string Department)

        :base(Id, Name, Address, Phone, Age)

    {

        this.Department = Department;

    }

    public void GetStudents(List<Student> studentDtos) {

        List<Student> testers = new List<Student>();

        foreach( var student in studentDtos ){

            Console.WriteLine("Lớp Tester STT{0} Name : {1} - Địa Chỉ : {2} - SĐT: {3} - Tuổi: {4} - Phòng Ban: {5}", 

                              student.Id, student.Name, student.Address, student.Phone, student.Age, student.Department );

        }

    }

    public List<Student> AddStudent(List<Student> studentDtos, Student member) {

        List<Student> students = new List<Student>();

        foreach( var student in studentDtos ){

            students.Add(new Student(student.Id ,student.Name, student.Address, 

                                   student.Phone, student.Age, student.Department));

        }

        students.Add(new Student(member.Id ,member.Name, member.Address, 

                                   member.Phone, member.Age, member.Department));

        return students;

    }

}