PerformanceTest.cs

using System;
using System.Diagnostics;
using System.Linq;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace Test
{
    [TestClass]
    public class PerformanceTest
    {
        [TestMethod]
        public void ForLoopPerformanceTest()
        {
            var array = Enumerable.Range(0, 10000000).ToArray();

            var stopwatch = new Stopwatch();
            stopwatch.Start();

            var result = CreateArrayByFor(array);
            //var result = CreateArrayByForeach(array);
            //var result = CreateArrayByLinq(array);

            stopwatch.Stop();
            var ms = stopwatch.ElapsedMilliseconds;
        }

        private int[] CreateArrayByFor(int[] source)
        {
            var result = new int[source.Length];
            for (int i = 0; i < result.Length; i++)
            {
                result[i] = source[i] * 10;
            }

            return result;
        }

        private int[] CreateArrayByForeach(int[] source)
        {
            var result = new int[source.Length];
            int index = 0;
            foreach (var each in source)
            {
                result[index++] = each * 10;
            }
            return result;
        }

        private int[] CreateArrayByLinq(int[] source)
        {
            return source.Select(x => x * 10).ToArray();
        }

        [TestMethod]
        public void ListForEachTest()
        {
            var list = Enumerable.Range(0, 10000000).ToList();
            var array = new int[list.Count];

            var stopwatch = new Stopwatch();
            stopwatch.Start();

            //for (int i = 0; i < list.Count; i++)
            //{
            //    array[i] = list[i];
            //}

            var index = 0;
            list.ForEach(each =>
            {
                array[index] = each;
                index++;
            });

            stopwatch.Stop();
            var ms = stopwatch.ElapsedMilliseconds;
        }

        [TestMethod]
        public void EnumGetHashCodeTest()
        {
            var stopwatch = new Stopwatch();
            stopwatch.Start();

            for (int i = 0; i < 1000000; i++)
            {
                //var test = (int)Hoge.Foo.GetHashCode();
                var test = ((int)Hoge.Foo).GetHashCode();
            }

            stopwatch.Stop();
            var ms = stopwatch.ElapsedMilliseconds;
        }

        // MEMO : http://stackoverflow.com/questions/7368652/what-is-it-that-makes-enum-hasflag-so-slow
        [TestMethod]
        public void EnumHasFlagTest()
        {
            var stopwatch = new Stopwatch();
            stopwatch.Start();

            var flags = Fuga.A | Fuga.C;
            for (int i = 0; i < 10000000; i++)
            {
                //var test = flags.HasFlag(Fuga.B);
                var test = (flags & Fuga.B) != 0;
            }

            stopwatch.Stop();
            var ms = stopwatch.ElapsedMilliseconds;
        }

        private enum Hoge
        {
            Foo
        }

        [Flags]
        public enum Fuga
        {
            A = 1,
            B = 2,
            C = 4,
            D = 8
        }
    }
}