using System;

using System.Collections.Generic;

using System.Collections.ObjectModel;

​

public class Program

{

    public static void Main()

    {

        IWidgetContainer container 

        container.AddNew("Apple", 4);

        container.AddNew("Grapefruit",7);

        Console.WriteLine( container.Validatate());

        container.AddNew("Pear",5);

        container.AddNew("Kiwi", 8);

        Console.WriteLine( container.Validatate());

    }

}

​

// Rules:

// 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 container my not exceed 15

​

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();

}