C# - lr3

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

namespace lr3
{
    public class Account
    {
        public string Number { get; private set; }
        public double Balance { get; private set; }
        public List<string> History { get; private set; }

        public Account(string num) { this.Number = num; this.Balance = 0; this.History = new List<string>(); }

        public void Add(double money)
        {
            this.Balance += money;
            this.History.Add("+ " + money.ToString());
        }

        public void Withdraw(double money)
        {
            Balance -= money;
            History.Add("- " + money.ToString());
        }

        public void ShowBalance()
        {
            Console.WriteLine(Balance);
        }

        public void ShowHistory()
        {
            Console.WriteLine($"Transaction history of account {Number}:");
            foreach (string transaction in History)
            {
                Console.WriteLine(transaction);
            }
        }
    }

    public class Client
    {
        public string FullName { get; private set; }
        public int Age { get; private set; }
        public string Job { get; private set; }
        private List<Account> Accounts { get; set; }

        public Client(string name, int age, string job)
        {
            this.FullName = name;
            this.Age = age;
            this.Job = job;
            this.Accounts = new List<Account>();
        }

        public void OpenAccount(string number)
        {
            Accounts.Add(new Account(number));
        }

        public void CloseAccount(string number)
        {
            for (int i = 0; i < Accounts.Count; ++i)
            {
                if (Accounts[i].Number == number)
                {
                    Accounts.RemoveAt(i);
                }
            }
        }

        public void Transaction(string account, char mode, double money)
        {
            for (int i = 0; i < Accounts.Count; ++i)
            {
                if (Accounts[i].Number == account)
                {
                    if (mode == '+') Accounts[i].Add(money);
                    else if (mode == '-') Accounts[i].Withdraw(money);
                    break;
                }
            }
        }

        public void ShowAccountHistory(string number)
        {
            for (int i = 0; i < Accounts.Count; ++i)
            {
                if (Accounts[i].Number == number)
                {
                    Console.WriteLine($"Account {number} history:");
                    Accounts[i].ShowHistory();
                }
            }
        }

        public void ShowAllAccounts()
        {
            Console.WriteLine($"All bank accounts of {this.FullName}: ");
            foreach (Account acc in Accounts)
            {
                Console.WriteLine($"Account {acc.Number} balance: {acc.Balance}");
            }
        }

        public void ShowClientInfo()
        {
            Console.WriteLine($"Public user info:\nFull name: {this.FullName}\nAge: {this.Age}\nJob: {this.Job}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Creating new user...");
            Client testClient = new Client("Saveliy Savvovich Tvorozhochkin", 228, "Dungeon");
            testClient.ShowClientInfo();

            Console.WriteLine($"\nOpening some accounts for {testClient.FullName}...");
            testClient.OpenAccount("22813371488");
            testClient.OpenAccount("00000000000");
            testClient.OpenAccount("12345678910");
            testClient.ShowAllAccounts();

            Console.WriteLine("\nSome test transactions coming...\n");
            testClient.Transaction("22813371488", '+', 42424242);
            testClient.Transaction("22813371488", '-', 42);
            testClient.Transaction("00000000000", '+', 2281488);
            testClient.Transaction("12345678910", '+', 228);
            testClient.ShowAllAccounts();

            Console.WriteLine($"\nChecking history of an account 22813371488...");
            testClient.ShowAccountHistory("22813371488");

            Console.WriteLine("\nClosing an account 22813371488...\n");
            testClient.CloseAccount("22813371488");
            testClient.ShowAllAccounts();
        }
    }
}