using System;    using System.Threading;    internal class Program    {        private static long _counter = 1;        private static void Main()        {            //下面程序显示两个线程如何并发访问一个名为counter的整形变量，一个线程让他递增5次，一个让他递减5次            Console.WriteLine("原始值：{0}", _counter);            var t1 = new Thread(F1);            var t2 = new Thread(F2);            t1.Start();            t2.Start();            t1.Join();            t2.Join();            Console.WriteLine("最终值：{0}", _counter);            Console.Read();        }        private static void F1()        {            for (int i = 0; i < 5; i++)            {                Interlocked.Increment(ref _counter);//原子性操作                Console.WriteLine(DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss:ff") + " 方法1：counter++：{0}", _counter);                Thread.Sleep(10);            }        }        private static void F2()        {            for (int i = 0; i < 5; i++)            {                Interlocked.Decrement(ref _counter);//原子性操作                Console.WriteLine(DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss:ff") + " 方法2：counter--：{0}", _counter);                Thread.Sleep(10);            }        }    }