using System;
using System.Diagnostics;
using System.Runtime.CompilerServices;

namespace ConsoleApplication1
{
    public static class Program
    {
        public const int Count = 100 * 1000 * 1000;

        [MethodImpl(MethodImplOptions.NoInlining)]
        public static int GetNumber_1(object value)
        {
            var v = value as int?;
            if (v != null)
                return v.GetValueOrDefault();

            return 0;
        }

        [MethodImpl(MethodImplOptions.NoInlining)]
        public static int GetNumber_2(object value)
        {
            if (value is int)
                return (int)value;

            return 0;
        }

        public static void Main()
        {
            var a = (object)0;

            GetNumber_1(a);
            GetNumber_2(a);

            Measure("Get number via: as int?", () =>
            {
                var x = a;

                for (var i = 0; i < Count; i++)
                {
                    GetNumber_1(x);
                }
            });

            Measure("Get number via: is int ", () =>
            {
                var x = a;

                for (var i = 0; i < Count; i++)
                {
                    GetNumber_2(x);
                }
            });
        }

        private static void Measure(string name, Action action)
        {
            GC.Collect();
            GC.WaitForPendingFinalizers();
            GC.Collect();

            var sw = Stopwatch.StartNew();
            action();
            sw.Stop();

            Console.WriteLine("{0,20}: {1,5} ms, ips: {2,15:N}", name, sw.ElapsedMilliseconds, Count / sw.Elapsed.TotalSeconds);
        }
    }
}