using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var ins=Singlton.Instance;

    }

}

​

public sealed class Singlton

{

    private Singlton(){}

    private static Singlton _instance;

    private static object _obj=new object();

    public static Singlton Instance

    {

        get

        {

            lock(_obj)

            {

                if(_instance==null)

                {

                    _instance=new Singlton();

                }

            }

            return _instance;

        }

    }

}

​

​

​