using System;

using System.Threading;

​

namespace data

{

    public class test

    {

        public static int count = 0;

        public test()

        {

            Interlocked.Increment(ref count);

        }

​

        ~test()

        {

            Interlocked.Decrement(ref count);

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            test obj1 = new test();

            test obj2 = new test();

            test obj3 = new test();

            Console.WriteLine(data.test.count);

        }

    }

}