static void Main(string[] args)
{
  //Action<int> func = Console.WriteLine;
  Action<int> func = number => number++;
  do
  {
    try
    {
      Console.Write("Iteration: ");
      var iterations = Convert.ToInt32(Console.ReadLine());
      Console.Write("Loop Type (for:0, foreach:1, List.ForEach:2, Array.ForEach:3): ");
      var loopType = Console.ReadLine();
      switch (loopType)
      {
        case "0":
          Console.WriteLine("FOR loop test for {0} iterations", iterations.ToString("0,0"));
          TestFor(iterations, func);
          break;
        case "1":
          Console.WriteLine("FOREACH loop test for {0} iterations", iterations.ToString("0,0"));
          TestForEach(iterations, func);
          break;
        case "2":
          Console.WriteLine("LIST.FOREACH test for {0} iterations", iterations.ToString("0,0"));
          TestListForEach(iterations, func);
          break;
        case "3":
          Console.WriteLine("ARRAY.FOREACH test for {0} iterations", iterations.ToString("0,0"));
          TestArrayForEach(iterations, func);
          break;
      }
    }
    catch (Exception ex)
    {
      Console.WriteLine(ex);
    }
    Console.Write("Continue?(Y/N)");
    Console.WriteLine("");
  } while (Console.ReadKey(true).Key != ConsoleKey.N);

  Console.WriteLine("Press any key to exit");
  Console.ReadKey();
}


static void TestFor(int iterations, Action<int> func)
{
  StartupTest(func);

  var watch = Stopwatch.StartNew();
  for (int i = 0; i < iterations; i++)
  {
    func(i);
  }
  watch.Stop();
  ShowResults("for loop test: ", watch);
}

static void TestForEach(int iterations, Action<int> func)
{
  StartupTest(func);
  var list = Enumerable.Range(0, iterations);

  var watch = Stopwatch.StartNew();
  foreach (var item in list)
  {
    func(item);
  }
  watch.Stop();
  ShowResults("foreach loop test: ", watch);
}

static void TestListForEach(int iterations, Action<int> func)
{
  StartupTest(func);
  var list = Enumerable.Range(0, iterations).ToList();

  var watch = Stopwatch.StartNew();
  list.ForEach(func);
  watch.Stop();
  ShowResults("list.ForEach test: ", watch);
}

static void TestArrayForEach(int iterations, Action<int> func)
{
  StartupTest(func);
  var array = Enumerable.Range(0, iterations).ToArray();

  var watch = Stopwatch.StartNew();
  Array.ForEach(array, func);
  watch.Stop();
  ShowResults("Array.ForEach test: ", watch);
}

static void StartupTest(Action<int> func)
{
  // clean up
  GC.Collect();
  GC.WaitForPendingFinalizers();
  GC.Collect();

  // warm up
  func(0);
}
static void ShowResults(string description, Stopwatch watch)
{
  Console.Write(description);
  Console.WriteLine(" Time Elapsed {0} ms", watch.ElapsedMilliseconds);
}