using System;

using System.Collections.ObjectModel;

​

public class Program

{

    public class StringCollection

    {

        public int CharCount { get; private set; }

​

        public void Add(string s) { }

​

        public void Clear() { }

    }

​

    public static void Main()

    {

        var stringCollection = new StringCollection();

​

        if (stringCollection.CharCount != 0)

        {

            Console.WriteLine("Collection error: CharCount != 0");

        }

​

        stringCollection.Add("One");

​

        if (stringCollection.CharCount != 3)

        {

            Console.WriteLine("Collection error: CharCount != 3");

        }

​

        stringCollection.Add("Two");

        stringCollection.Add("Three");

​

        if (stringCollection.CharCount != 11)

        {

            Console.WriteLine("Collection error: CharCount != 11");

        }

​

        stringCollection.Clear();

​

        if (stringCollection.CharCount != 0)

        {

            Console.WriteLine("Collection error: CharCount != 0");

        }

    }

}