static void Main(string[] args) { var stopWatch = new StopWatch(); while (true) { Console.WriteLine("\nPress 1 to \"start\" the stop watch"); Console.WriteLine("Press 2 to \"stop\" the stop watch"); Console.Write("Type here: "); try { var input = Convert.ToInt32(Console.ReadLine()); if (input == 1) { stopWatch.Start(); } else if (input == 2) { stopWatch.Stop(); Console.WriteLine("Duration: {0}", stopWatch.Calculate()); } else { Console.WriteLine("Invalid input! Try again!"); } } catch (Exception) { Console.WriteLine("Invalid input! Try again!"); continue; } } }