using System;

using System.Diagnostics;

public class Program

{

    private static void Benchmark(Action act, int iterations)

    {

        GC.Collect();

        act.Invoke(); // run once outside of loop to avoid initialization costs

        Stopwatch sw = Stopwatch.StartNew();

        for (int i = 0; i < iterations; i++)

        {

            act.Invoke();

        }

        sw.Stop();

        Console.WriteLine((sw.ElapsedTicks).ToString());

    }

​

    public static void Main(string[] args)

    {

        var input = 5.5f;

        Benchmark(() => 

                  { 

                      var half = input >= 0 ? 0.5 : -0.5;

                      int result = (int)(input + half); 

                      if (result != 6)

                          throw new Exception();

                  }, 100000);

        Benchmark(() => 

                  { 

                      int result = (int)(Math.Round(input));

                      if (result != 6)

                          throw new Exception();

                  }, 100000);

        Benchmark(() => 

                  { 

                      int result = (int)(Convert.ToInt32(input));

                      if (result != 6)

                          throw new Exception();

                  }, 100000);

    }

}