using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        OuterClass1 oc1 = new OuterClass1();

        var cat1 = oc1.AddSomething(new Cat("cat1", "meow"));

        var cat2 = oc1.AddSomething(new Cat("cat2", "hiss"));

        var dog1 = oc1.AddSomething(new Dog("dog1"));

        var cat1instance = oc1.GetSomething("cat1");

        Console.WriteLine(cat1instance.Name);

    }

}

​

public interface ISomething1

{

    string Name { get; }

}

​

public class OuterClass1

{

    private List<ISomething1> Somethings = new List<ISomething1>();

​

    internal ISomething1 AddSomething(ISomething1 newsomething)

    {

        Somethings.Add(newsomething);

        return newsomething;

    }

​

    internal ISomething1 GetSomething(string name)

    {

        return Somethings.FirstOrDefault(smtng => smtng.Name == name);

    }

    private class Something1: ISomething1

    {

        public Something1(string name) { Name = name; }

        public string Name { get; }

    }

}

​

public class Cat : ISomething1

{

    public Cat(string name, string sound = "")

    {

        Name = name;

        CatSound = sound;

    }

    public string Name { get; }

    public string CatSound { set; get; }

}

​

public class Dog : ISomething1

{

    public Dog(string name, string sound = "")

    {

        Name = name;

        DogSound = sound;

    }

​

    public string Name { get; }

    public string DogSound { set; get; }

}

​

public class Tiger : ISomething1

{

    public Tiger(string name) { Name = name; }

    public string Name { get; }

}