using System;

using System.Linq;

​

public class SoldItem

{

    public string ID { get; set; }

    public int AmountSold { get; set; }

    public int PricePerItem { get; set; }

}

​

public class Customer

{

    public string Name { get; set; }

    public bool IsPremiumMember { get; set; }

    public SoldItem[] ItemsPurchased { get; set; }

}

​

public class ItemDetails {

    public string ID { get; set; }

    public int RecommendedPrice { get; set; }

    public string Description { get; set; }

}

​

public class Program

{

    private static Customer[] Customers = new Customer[] {

        new Customer {

            Name = "Matt",

            IsPremiumMember = false,

            ItemsPurchased = new SoldItem[] {

                new SoldItem { ID = "Shoe", AmountSold = 2, PricePerItem = 20 },

                new SoldItem { ID = "Hat", AmountSold = 1, PricePerItem = 30 },

                new SoldItem { ID = "Car", AmountSold = 1, PricePerItem = 5000 }

            }

        },

        new Customer {

            Name = "John",

            IsPremiumMember = true,

            ItemsPurchased = new SoldItem[] {

                new SoldItem { ID = "Bike", AmountSold = 1, PricePerItem = 300 }

            }

        },

        new Customer {

            Name = "Ryan",

            IsPremiumMember = true,

            ItemsPurchased = new SoldItem[] {

                new SoldItem { ID = "Watermellon", AmountSold = 5, PricePerItem = 9 },

                new SoldItem { ID = "Cabbage", AmountSold = 10, PricePerItem = 4 },

                new SoldItem { ID = "Coffee Cup", AmountSold = 20, PricePerItem = 5 },

                new SoldItem { ID = "Tyre", AmountSold = 4, PricePerItem = 90 }

            }

        },

        new Customer {

            Name = "Jake",

            IsPremiumMember = true,

            ItemsPurchased = new SoldItem[0]

        },

        // ...potentially many more customers

    };

​

    private static ItemDetails[] AllItemDetails = new ItemDetails[] {

        new ItemDetails { ID = "Shoe", Description = "A Shoe. Very fancy.", RecommendedPrice = 5, },

        new ItemDetails { ID = "Hat", Description = "", RecommendedPrice = 20, },

        new ItemDetails { ID = "Car", Description = "", RecommendedPrice = 5000, },

        new ItemDetails { ID = "Bike", Description = "", RecommendedPrice = 150, },

        new ItemDetails { ID = "Watermellon", Description = "", RecommendedPrice = 9, },

        new ItemDetails { ID = "Cabbage", Description = "", RecommendedPrice = 3, },

        new ItemDetails { ID = "Coffee Cup", Description = "", RecommendedPrice = 7, },

        new ItemDetails { ID = "Tyre", Description = "", RecommendedPrice = 80, },

        // ...potentially many more items

    };

​

    public static void Main(string[] args)

    {

        Console.WriteLine($"There have been {Customers.Count()} customers.");

        Console.WriteLine("The 'PremiumMember' who has spent the most money is:");

        // todo: find the highest-spending customer that is a PremiumMember and print their name

​

        Console.WriteLine("The total revenue if the recommended price was used is:");

        // todo: find what the total revenue for all customers would have been if the RecommendedPrice from AllItemDetails was used for each item.

    }

}

​