using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Hosting;

​

public class Program

{

    public static void Main()

    {

        var host = Host.CreateDefaultBuilder()

        .ConfigureServices((_, services) =>

        {

            services.AddSingleton<Example>();

        }).Build();

        var scope = host.Services.CreateScope();

        var svcs = scope.ServiceProvider;

        svcs.GetRequiredService<Example>().Run();   

    }

}

​

// Example Requirements:

//  - Widget name must be at least 5 characters long

//  - Widget ids must be created by the an ID Factory

//  - All Widgets must have a unique names

//  - A the total size of all widgets in a single container may not exceed 15

​

public class Example{

​

    private IWidgetContainer widget_container;

    public Example(IWidgetContainer widgetContainer){

    }

    public void Run(){

        widget_container.AddNew("Apple", 4);

        widget_container.AddNew("Grapefruit",7);

        Console.WriteLine(widget_container.Validatate());

        widget_container.AddNew("Pear",5);

        widget_container.AddNew("Kiwi", 8);

        Console.WriteLine(widget_container.Validatate());

    }

}

​

public interface IWidgetContainer{

    IWidget AddNew(string widget_name, int size);

    ReadOnlyCollection<IWidget> Widgets {get;}

    List<string> Validatate();

}

​

public interface IWidget{

    int Id{get;}

    string Name{get;set;}

    int Size {get; set;}

}

​

public interface IIdFactory{

    int CreateNewId();

}

​

​

​

​