using System.Collections.Generic;
private static List<SalesRecord> salesRecords = new();
public static void Main()
var currentServiceProvider = "AWS";
var accManager = GetAccountManager(currentServiceProvider);
Console.WriteLine("Enter User ID:");
var userId = Console.ReadLine();
Console.WriteLine("Enter Password:");
var password = Console.ReadLine();
if (accManager.Authenticate(userId, password))
Random random = new Random();
for (var i = 0; i < 10000; i++)
var item = i < 4000 ? "A" : i < 8000 ? "B" : "C";
salesRecords.Add(new SalesRecord(item, random.Next()));
Console.WriteLine("Which item do you want to view? (A/B/C):");
var chosenItem = Console.ReadLine();
var chosenRecord = salesRecords.Where(x => x.Item == chosenItem).OrderByDescending(x => x.Qty);
foreach (var chosen in chosenRecord)
Console.WriteLine(chosen.Item + " " + chosen.Qty);
public static IAccountManager GetAccountManager(string serviceProvider)
if (serviceProvider == "AWS")
return new AzureService();
public struct SalesRecord
public string Item { get; set; }
public int Qty { get; set; }
public SalesRecord(string item)
public SalesRecord(string item, int qty)
public interface IAccountManager
public bool Authenticate(string userId, string password);
public class AwsService : IAccountManager
public bool Authenticate(string userId, string password)
return userId == "aws" && password == "abc123";
public bool DeleteUser(string userId)
public class AzureService : IAccountManager
public bool AuthUser(string userId, string password)
return userId == "azure" && password == "abc321";
public bool RemoveUser(string userId)
public bool Authenticate(string userId, string password)
return this.AuthUser(userId, password);