#region 监视文件夹的变化             FileSystemWatcher watcher = new FileSystemWatcher();             watcher.Path = "f:\\";             watcher.NotifyFilter =//被监控的方面                NotifyFilters.LastWrite |                NotifyFilters.FileName |                NotifyFilters.DirectoryName;             // 订阅一些事件，当它被触发时（.net(windows)底层触发它，我们不用管），执行我们的方法             watcher.Changed += (object source, FileSystemEventArgs e) =>             {                 Console.WriteLine("文件{0}已经被修改,修改类型{1}", e.FullPath, e.ChangeType.ToString());             };             watcher.Created += (object source, FileSystemEventArgs e) =>             {                 Console.WriteLine("文件{0}被建立", e.FullPath);             };             watcher.Deleted += (object source, FileSystemEventArgs e) =>             {                 Console.WriteLine("文件{0}已经被删除", e.FullPath);             };             watcher.Renamed += (object source, RenamedEventArgs e) =>             {                 Console.WriteLine("文件{0}的名称已经从{1}变成了{2}", e.OldFullPath, e.OldName, e.Name);             };             // 为true表示开启FileSystemWatcher组件，反之我们的监控将不启作用             watcher.EnableRaisingEvents = true;             #endregion

#region xor两个变量交换             int a = 2;             int b = 3;             Console.WriteLine("a={0}", a);             Console.WriteLine("b={0}", b);             a = a ^ b ^ (b = a);             Console.WriteLine("a={0}", a);             Console.WriteLine("b={0}", b);             #endregion