C#计算一段程序运行时间的三种方法（转）

第一种方法利用System.DateTime.Now

public static void SubTest()
        {
            DateTime beforeDT = System.DateTime.Now;
            int[] a = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
            //Shuffle(a) is the function you want to test.
            Shuffle(a);
            DateTime afterDT = System.DateTime.Now;
            TimeSpan ts = afterDT.Subtract(beforeDT);
            Console.WriteLine("DateTime costed for Shuffle function is: {0}ms",ts.TotalMilliseconds);
        }

第二种用Stopwatch类(System.Diagnostics)

public static void SubTest()
        {
            Stopwatch sw = new Stopwatch();
            sw.Start();
            //Shuffle(a) is the function you want to test.
            int[] a = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 };
            Shuffle(a);
            sw.Stop();
            TimeSpan ts = sw.Elapsed;
            Console.WriteLine("DateTime costed for Shuffle function is: {0}ms", ts.TotalMilliseconds);
        }