Кадровый учет

using System;

namespace CSLight
{
    internal class Program
    {
        static void Main()
        {
            const string CommandAddDossier = "1";
            const string CommandDeduceDossiers = "2";
            const string CommandDeleteDossier = "3";
            const string CommandSearchLastName = "4";
            const string CommandExit = "5";

            string[] fullNames = new string[0];
            string[] posts = new string[0];

            bool isWork = true;

            Console.CursorVisible = false;

            while (isWork)
            {
                Console.WriteLine("Меню команд:");
                Console.SetCursorPosition(0, 2);
                Console.WriteLine(CommandAddDossier + " - Добавить досье");
                Console.WriteLine(CommandDeduceDossiers + " - Вывести все досье");
                Console.WriteLine(CommandDeleteDossier + " - Удалить досье");
                Console.WriteLine(CommandSearchLastName + " - Поиск по фамилии");
                Console.WriteLine(CommandExit + " - Выход");
                Console.SetCursorPosition(0, 8);
                Console.Write("Введите команду: ");

                switch (Console.ReadLine())
                {
                    case CommandAddDossier:
                        FillDossier(ref fullNames, ref posts);
                        break;

                    case CommandDeduceDossiers:
                        ShowDossier(fullNames, posts);
                        break;

                    case CommandDeleteDossier:
                        DeleteDossier(ref fullNames, ref posts);
                        break;

                    case CommandSearchLastName:
                        FindLastName(fullNames, posts);
                        break;

                    case CommandExit:
                        isWork = false;
                        break;

                    default:
                        Console.WriteLine("\nОшибка. Введена неверная команда...");
                        break;
                }

                Console.ReadKey(true);
                Console.Clear();
            }
        }

        static void FillDossier(ref string[] fullNames, ref string[] posts)
        {
            Console.Write("\nВведите ФИО: ");
            fullNames = AddData(fullNames);

            Console.Write("\nВведите должность: ");
            posts = AddData(posts);
        }

        static void ShowDossier(string[] fullNames, string[] posts)
        {
            int sequenceNumber = 1;

            if (fullNames.Length == 0)
            {
                Console.WriteLine("\nНа данный момент у вас нет ни одного досье.");
            }
            else
            {
                for (int i = 0; i < fullNames.Length; i++)
                {
                    Console.WriteLine($"\n| {sequenceNumber++}. {fullNames[i]} - {posts[i]} |");
                }
            }
        }

        static void DeleteDossier(ref string[] fullNames, ref string[] posts)
        {
            int deletedNumber;

            Console.Write("\nВведите номер досье на удаление: ");

            deletedNumber = ReadInt() - 1;

            if (deletedNumber < 0 || fullNames.Length == 0 || deletedNumber + 1 > fullNames.Length)
            {
                Console.WriteLine("\nТакого номера нет.");
            }
            else
            {
                fullNames = DeleteElement(fullNames, deletedNumber);
                posts = DeleteElement(posts, deletedNumber);
            }
        }

        static void FindLastName(string[] fullNames, string[] posts)
        {
            string[] lastName;

            string lastNameInput;

            bool isFound = false;

            Console.Write("\nВведите фамилию: ");

            lastNameInput = Console.ReadLine();

            for (int i = 0; i < fullNames.Length; i++)
            {
                lastName = fullNames[i].Split(' ');

                if (lastName[0].ToLower() == lastNameInput.ToLower())
                {
                    Console.WriteLine($"\n| {fullNames[i]} - {posts[i]} |");

                    isFound = true;
                }
            }

            if (isFound == false)
            {
                Console.WriteLine("\nТакой фамилии нет.");
            }
        }

        static string[] AddData(string[] array)
        {
            string[] tempArray = new string[array.Length + 1];

            for (int i = 0; i < array.Length; i++)
            {
                tempArray[i] = array[i];
            }

            array = tempArray;
            array[array.Length - 1] = Console.ReadLine();

            return array;
        }

        static string[] DeleteElement(string[] array, int index)
        {
            string[] tempArray = array;
            array = new string[tempArray.Length - 1];

            for (int i = 0; i < array.Length; i++)
            {
                if (i == index || index < i)
                {
                    array[i] = tempArray[i + 1];
                }
                else
                {
                    array[i] = tempArray[i];
                }
            }

            return array;
        }

        static int ReadInt()
        {
            int number = 0;

            while (int.TryParse(Console.ReadLine(), out number) == false)
            {
                Console.WriteLine("\nВведите число.\n");
            }

            return number;
        }
    }
}