using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    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();

        // ... Authenticate user ...

        while (!accManager.Authenticate(userId, password))

        {

            Console.WriteLine("User not found!");

            Console.WriteLine("Enter User ID:");

            userId = Console.ReadLine();

            Console.WriteLine("Enter Password:");

            password = Console.ReadLine();

        }

​

        for (var i = 0; i < 10000; i++)

        {

            var item = i < 4000 ? "A" : i < 8000 ? "B" : "C";

            salesRecords.Add(new SalesRecord(item));

        }

​

        // ... Propagate salesRecords with random quantities ...

        Console.WriteLine("Which item do you want to view? (A/B/C):");

        var chosenItem = Console.ReadLine();

    // ... Display items by filtering and sorting them in descending order with linq expression ...

    }

​

    public static IAccountManager GetAccountManager(string serviceProvider)

    {

        if (serviceProvider == "AWS")

        {

            return new AwsService();

        }

        else

        {

            return new AzureService();

        }

    }

}

​

public struct SalesRecord

{

    public string Item { get; set; }

​

    public int Qty { get; set; }

​

    public SalesRecord(string item)

    {

        Random rand = new Random();

        Item = item;

        Qty = rand.Next(1, 101);

    }

}

​

public interface IAccountManager

{

    public bool Authenticate(string userId, string password);

}

​

// ... Interface Implementations ...

public class AwsService : IAccountManager

{

    public bool Authenticate(string userId, string password)

    {

        return userId == "aws" && password == "abc123";

    }

​

    public bool DeleteUser(string userId)

    {

        return true;

    }

}

​

public class AzureService : IAccountManager

{

    public bool Authenticate(string userId, string password)

    {

        return userId == "azure" && password == "abc321";

    }

​

    public bool RemoveUser(string userId)

    {

        return true;

    }

}