SingletonPattern

using System;

namespace SingletonPattern

{

    class Singleton

    {

        private static Singleton _SingletoneInstance;

        private Singleton() { }

        public static Singleton _GetInstance()

        {

            if (_SingletoneInstance == null) _SingletoneInstance = new Singleton();

            return _SingletoneInstance;

        }

    }

    class Program

    {

        static void Main(string[] args)

        {

            Singleton _InstanceA = Singleton._GetInstance();

            Singleton _InstanceB = Singleton._GetInstance();

            if (_InstanceA == _InstanceB) Console.WriteLine("isEqual : " + _InstanceA + "==" + _InstanceB);

            Singleton _InstanceC = Singleton._GetInstance();

            if (_InstanceB == _InstanceC) Console.WriteLine("isEqual : " + _InstanceB + "==" + _InstanceC);

        }

    }

}