View difference between Paste ID: nvfGAn2h and exeaWwWQ

 using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Linq;
 using System.IO;
 using System.Runtime.Serialization;
 using System.Runtime.Serialization.Formatters.Binary;
 using System.Text;
 
 namespace IMJunior
 {
     class Program
     {
         static UserRepository _users = new UserRepository();
 
         static void Main()
         {
             while (true)
             {
                 string command = Console.ReadLine();
                 switch (command)
                 {
                     case "Update":
                         Console.WriteLine("Id:");
                         int id = Convert.ToInt32(Console.ReadLine());
                         Console.WriteLine("Name:");
                         string name = Console.ReadLine();
                         Console.WriteLine("Money:");
                         float money = (float)Convert.ToDouble(Console.ReadLine());
                         Console.WriteLine(UpdateUser(id, name, money));
 
                         break;
                     case "Create":
 
                         Console.WriteLine("Name:");
                         string name2 = Console.ReadLine();
                         Console.WriteLine("Money:");
                         float money2 = (float)Convert.ToDouble(Console.ReadLine());
                         Console.WriteLine(CreateUser(name2, money2));
 
                         break;
                     case "Show":
                         Console.WriteLine(ShowUsers());
                         break;
                 }
             }
         }
 
         static string UpdateUser(int id, string name, float? money)
         {
             User user = _users.GetById(id);
             if (user == null) return "Вы не можете обновить это пользователя";
 
             if (name != null)
             {
                 user.Name = name;
             }
             if (name != null)
             {
                 user.Money = (float)money;
             }
 
             return "Обновление прошло успешно";
         }
 
         static string CreateUser(string name, float money)
         {
             User user = _users.Create();
 
             user.Name = name;
             user.Money = money;
 
             return "Пользователь создан";
         }
 
         static string ShowUsers()
         {
             StringBuilder response = new StringBuilder();
 
             foreach (var user in _users.GetAll())
             {
                 response.Append($"[{user.Id}] {user.Name} - {user.Money}\n");
             }
 
             return response.ToString();
         }
     }
 
     class UserRepository
     {
         private readonly List<User> _users = new List<User>();
 
         public UserRepository()
         {
             using (var stream = File.Open($"database/users.database", FileMode.OpenOrCreate))
             {
                 if (stream.Length == 0) return;
 
                 IFormatter formater = new BinaryFormatter();
                 _users = (List<User>)formater.Deserialize(stream);
 
                 foreach (var user in _users)
                 {
                     user.OnDirty = Update;
                 }
             }
         }
 
         public User[] GetAll()
         {
             return _users.ToArray();
         }
 
         public User GetById(int id)
         {
             return _users.FirstOrDefault((user) => user.Id == id);
         }
 
         public User Create()
         {
             int id = 0;
             if (_users.Count > 0)
                 id = _users.Max((u) => u.Id) + 1;
 
             User user = new User(id);
             user.OnDirty = Update;
             _users.Add(user);
             SaveList();
 
             return user;
         }
 
         public void Update(User user)
         {
             //
             SaveList();
         }
 
         public void Delete(User user)
         {
             _users.Remove(user);
             SaveList();
         }
 
         private void SaveList()
         {
             using (var stream = File.Open($"database/users.database", FileMode.OpenOrCreate))
             {
                 IFormatter formater = new BinaryFormatter();
                 formater.Serialize(stream, _users);
 
                 stream.Flush();
             }
         }
     }
 
     delegate void DirtyHandler(User user);
 
     [Serializable]
     class User
     {
         public int Id { get; private set; }
         private string _name;
         private float _money;
 
         [NonSerialized]
         public DirtyHandler OnDirty;
 
         public string Name {
             get => _name;
             set
             {
                 _name = value;
                 if(OnDirty != null)
                 {
                     OnDirty(this);
                 }
             }
         }
         public float Money {
             get => _money;
             set
             {
                 _money = value;
                 if (OnDirty != null)
                 {
                     OnDirty(this);
                 }
             }
         }
 
         public User(int id)
         {
             Id = id;
         }
     }
 }