using System;

using System.Collections.Generic;

using System.Diagnostics;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var stopWatch = new Stopwatch();

        var runCount = 100;

        var method1Runs = new TimeSpan[runCount];

        var method2Runs = new TimeSpan[runCount];

​

        Console.WriteLine(string.Format("Results running DotNetPerls' test methods {0} times.", runCount));

​

        var listA = new List<int>(100);

        for (var i = 0; i < runCount; i++)

        {

            stopWatch.Restart();

            Method1(listA);

            stopWatch.Stop();

            method1Runs[i] = stopWatch.Elapsed;

        }

​

        var listB = new List<int>(100);

        for (var i = 0; i < runCount; i++)

        {

            stopWatch.Restart();

            Method2(listB);

            stopWatch.Stop();

            method2Runs[i] = stopWatch.Elapsed;

        }

​

        ReportMethodResults(method1Runs, "Clear");

        Console.WriteLine();

        ReportMethodResults(method2Runs, "New");

    }

​

    static List<int> Method1(List<int> list)

    {

        // ... Clear same list, then add 100 ints.

        list.Clear();

        for (int i = 0; i < 100; i++)

        {

            list.Add(i);

        }

        return list;

    }

​

    static List<int> Method2(List<int> list)

    {

        // ... New list, then add 100 ints.

        list = new List<int>(100);

        for (int i = 0; i < 100; i++)

        {

            list.Add(i);

        }

        return list;

    }

​

    static void ReportMethodResults(IEnumerable<TimeSpan> timeSpans, string methodName)

    {

​

        var longestTime = timeSpans.Max(o => o.TotalNanoseconds());

        var shortestTime = timeSpans.Min(o => o.TotalNanoseconds());

        var averageTime = timeSpans.Average(o => o.TotalNanoseconds());

        var medianTime = timeSpans.Median(o => o.TotalNanoseconds());

​

        Console.WriteLine(string.Format("Longest time {0}: {1}ns", methodName, longestTime));

        Console.WriteLine(string.Format("Shortest time {0}: {1}ns", methodName, shortestTime));

        Console.WriteLine(string.Format("Average time {0}: {1}ns", methodName, averageTime));

        Console.WriteLine(string.Format("Median time {0}: {1}ns", methodName, medianTime));

    }

}

​

static class ExtensionMethods

{

    public static double TotalNanoseconds(this TimeSpan timeSpan)

    {

        const int nanosecondsInMillisecond = 1000000;

        return timeSpan.TotalMilliseconds * nanosecondsInMillisecond;

    }

​

    public static double Median<TSource>(this IEnumerable<TSource> source, Func<TSource, double> selector)

    {

        var orderedItems = source.Select(selector).OrderBy(o => o).ToArray();

        if (orderedItems.Length == 0)

            throw new ArgumentOutOfRangeException("Cannot find the Median of an empty set.");

​

        if (orderedItems.Length % 2 == 1)

            return orderedItems[(orderedItems.Length - 1) / 2];

        else

        {

            var itemAIndex = orderedItems.Length / 2;

            var itemBIndex = itemAIndex - 1;

            return (orderedItems[itemAIndex] + orderedItems[itemBIndex]) / 2;

        }

    }

}