using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SingletoneExample {

    class Singleton {
        private static Singleton instance = new Singleton();

        public int flag;

        private Singleton() { }

        public static Singleton getInstance() {
            return instance;
        }
    }

    class SimpleSingleton
    {
        static void Main(string[] args)
        {
            Singleton single = Singleton.getInstance();
            single.flag = 10;
            Console.WriteLine("single flag = " + single.flag);

            Singleton single1 = Singleton.getInstance();
            Console.WriteLine("single1 flag = " + single1.flag);
            Console.ReadLine();
        }
    }
}