AddressBook (interfases)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    interface IFriend
    {
        string Surname { get; set; }
        string Telephone { get; set; }
        void Print();
    }
    interface IEmployee
    {
        string WorkPhone { get; set; }
        string Position { get; set; }
    }
    interface ICompetitor
    {
        string HomePhone { get; set; }
        string HomeAddress { get; set; }
    }

    class Friend : IFriend
    {
        public string Surname { get; set; }

        public string Telephone { get; set; }
        public Friend(string surname = "", string telephone = "")
        {
            Surname = surname;
            Telephone = telephone;
        }
        public void Print()
        {
            Console.WriteLine("ФИО: " + Surname + ". Номер: " + Telephone);
        }
    }
    class Employee : IFriend, IEmployee
    {

        public string Surname { get; set; }
        public string Telephone { get; set; }
        public string WorkPhone { get; set; }
        public string Position { get; set; }
        public Employee(string surname = "", string telephone = "", string workPhone = "", string position = "")
        {
            Surname = surname;
            Telephone = telephone;
            WorkPhone = workPhone;
            Position = position;
        }
        public void Print()
        {
            Console.WriteLine("ФИО: " + Surname + ". Номер: " + Telephone);
            Console.WriteLine("рабочий тел.: " + WorkPhone + " должность: " + Position);
        }
    }
    class Competitor : IFriend, IEmployee, ICompetitor
    {

        public string Surname { get; set; }
        public string Telephone { get; set; }
        public string WorkPhone { get; set; }
        public string Position { get; set; }
        public string HomePhone { get; set; }
        public string HomeAddress { get; set; }
        public Competitor(string surname = "", string telephone = "", string workPhone = "", string position = "", string homePhone = "", string homeAddress = "")
        {
            Surname = surname;
            Telephone = telephone;
            WorkPhone = workPhone;
            Position = position;
            HomePhone = homePhone;
            HomeAddress = homeAddress;
        }
        public void Print()
        {
            Console.WriteLine("ФИО: " + Surname + ". Номер: " + Telephone);
            Console.WriteLine("рабочий тел.: " + WorkPhone + " должность: " + Position);
            Console.WriteLine("дом. тел.: " + HomePhone + " дом. адрес: " + HomeAddress);
        }
    }
    class AddressBook
    {
        Friend[] arrFriend;
        Employee[] arrEmployee;
        Competitor[] arrCompetitor;

        public AddressBook()
        {
            arrFriend = new Friend[0];
            arrEmployee = new Employee[0];
            arrCompetitor = new Competitor[0];
        }

        public void AddSubscriber(object obj, string ch)
        {
            switch (ch)
            {
                case "друг":
                    Friend[] newarrF = new Friend[arrFriend.Length + 1];
                    for (int i = 0; i < arrFriend.Length; i++)
                    {
                        newarrF[i] = arrFriend[i];
                    }
                    newarrF[arrFriend.Length] = (Friend)obj;
                    arrFriend = newarrF;
                    break;
                case "сотрудник":
                    Employee[] newarrE = new Employee[arrEmployee.Length + 1];
                    for (int i = 0; i < arrEmployee.Length; i++)
                    {
                        newarrE[i] = arrEmployee[i];
                    }
                    newarrE[arrEmployee.Length] = (Employee)obj;
                    arrEmployee = newarrE;
                    break;
                case "конкурент":
                    Competitor[] newarrC = new Competitor[arrCompetitor.Length + 1];
                    for (int i = 0; i < arrCompetitor.Length; i++)
                    {
                        newarrC[i] = arrCompetitor[i];
                    }
                    newarrC[arrCompetitor.Length] = (Competitor)obj;
                    arrCompetitor = newarrC;
                    break;
            }

        }
        public void PrintBook()
        {
            Console.WriteLine("\nДрузья:\n");
            foreach (Friend a in arrFriend)
            {
                a.Print();
            }
            Console.WriteLine("\nСотрудники:\n");
            foreach (Employee a in arrEmployee)
            {
                a.Print();
            }
            Console.WriteLine("\nКонкуренты:\n");
            foreach (Competitor a in arrCompetitor)
            {
                a.Print();
            }
        }

        class Program
        {
            static readonly string arrow = "=> ";
            static readonly string[] menu = { "Добавить абонента", "Просмотреть книгу", "Выйти из приложения" };
            static readonly string[] submenu = { "Друг", "Сотрудник", "Конкурент", "Возврат в предыдущее меню" };
            static void PrintMenu(string[] arr, int choice)
            {
                Console.Clear();
                for (int i = 0; i < arr.Length; i++)
                {
                    if (i == choice)
                    {
                        Console.Write(arrow);
                        Console.WriteLine(arr[i]);
                    }
                    else
                    {
                        Console.Write("   ");
                        Console.WriteLine(arr[i]);
                    }
                }
            }
            static void SelectFunc(AddressBook a, int choice)
            {
                Console.CursorVisible = false;
                int ch = 0;
                switch (choice)
                {
                    case 0:
                        while (true)
                        {
                            PrintMenu(submenu, ch);
                            switch (Console.ReadKey(true).Key)
                            {
                                case ConsoleKey.UpArrow:
                                    if (ch != 0)
                                    {
                                        ch--;
                                    }
                                    break;
                                case ConsoleKey.DownArrow:
                                    if (ch != submenu.Length - 1)
                                    {
                                        ch++;
                                    }
                                    break;
                                case ConsoleKey.Enter:
                                    Console.CursorVisible = true;
                                    switch (ch)
                                    {
                                        case 0:
                                            Console.WriteLine("Заполните следующие поля: ФИО, телефон");
                                            Friend f = new Friend(Console.ReadLine(), Console.ReadLine());
                                            a.AddSubscriber(f, "друг");
                                            break;
                                        case 1:
                                            Console.WriteLine("Заполните следующие поля: ФИО, телефон, рабочий телефон, должность");
                                            Employee e = new Employee(Console.ReadLine(), Console.ReadLine(), Console.ReadLine(), Console.ReadLine());
                                            a.AddSubscriber(e, "сотрудник");
                                            break;
                                        case 2:
                                            Console.WriteLine("Заполните следующие поля: ФИО, телефон, рабочий телефон, должность, домашний телефон, домашний адрес");
                                            Competitor c = new Competitor(Console.ReadLine(), Console.ReadLine(), Console.ReadLine(), Console.ReadLine(), Console.ReadLine(), Console.ReadLine());
                                            a.AddSubscriber(c, "конкурент");
                                            break;
                                        case 3:
                                            return;
                                    }
                                    break;
                            }
                        }
                        break;
                    case 1:
                        a.PrintBook();
                        Console.ReadKey();
                        break;
                    case 2:
                        System.Environment.Exit(0);
                        break;
                }
            }

            static void Main(string[] args)
            {
                AddressBook a = new AddressBook();
                Console.CursorVisible = false;
                int choice = 0;

                while (true)
                {
                    PrintMenu(menu, choice);
                    switch (Console.ReadKey(true).Key)
                    {
                        case ConsoleKey.UpArrow:
                            if (choice != 0)
                            {
                                choice--;
                            }
                            break;
                        case ConsoleKey.DownArrow:
                            if (choice != menu.Length - 1)
                            {
                                choice++;
                            }
                            break;
                        case ConsoleKey.Enter:
                            Console.CursorVisible = true;
                            SelectFunc(a, choice);
                            break;
                    }
                }
            }
        }
    }
}