using System;

using System.Diagnostics;

using System.Threading;

​

public class Program

{

    public static void Main()

    {

        Stopwatch timer = Stopwatch.StartNew();

        Thread.Sleep(1234);

        timer.Stop();

        TimeSpan timeSpan = timer.Elapsed;

        Console.WriteLine("Total processing time... {0:00}:{1:00}:{2:00}.{3}", timeSpan.Hours, timeSpan.Minutes, timeSpan.Seconds, timeSpan.Milliseconds);

        // OUTPUT   Total processing time... 00:00:01.243

        DateTime start = DateTime.Now;

        Console.WriteLine("Process starting at: " + start.ToString("dd/MM/yyyy hh:mm:ss tt"));

        Thread.Sleep(1234);

        DateTime end = DateTime.Now;

        Console.WriteLine("Process finished at: " + end.ToString("dd/MM/yyyy hh:mm:ss tt"));

        TimeSpan diff = (end  - start);

        Console.WriteLine("Total elapsed time:  {0:00}:{1:00}:{2:00}.{3}", diff.Hours, diff.Minutes, diff.Seconds, diff.Milliseconds);

        // OUTPUT

        // Process starting at: 29/11/2018 12:12:57 AM

        // Process finished at: 29/11/2018 12:12:59 AM

        // Total elapsed time:  00:00:01.234

    }

}

​