using System;
using System.Diagnostics;
using System.Linq;

class Program
{

    static void Main()
    {
        Console.WindowHeight = 30;
        Console.WindowWidth = 120;

        const int RepeatCount = 100 * 1000;
        const int Size = 10 * 1000;
        var rnd = new Random(0);

        var items = Enumerable.Range(1, Size)
            .Select(i => (long)rnd.Next())
            .ToArray();
        var list = items.ToList();
        var enumerable = list.AsEnumerable();

        Measure("array", () =>
        {
            long result = 0;
            for (int i = 0; i < RepeatCount; i++)
            {
                result = 0;
                foreach (var item in items)
                {
                    result += item;
                }
            }
            return RepeatCount * Size;
        });

        Measure("list", () =>
        {
            long result = 0;
            for (int i = 0; i < RepeatCount; i++)
            {
                result = 0;
                foreach (var item in list)
                {
                    result += item;
                }
            }
            return RepeatCount * Size;
        });

        Measure("enumerable", () =>
        {
            long result = 0;
            for (int i = 0; i < RepeatCount; i++)
            {
                result = 0;
                foreach (var item in enumerable)
                {
                    result += item;
                }
            }
            return RepeatCount * Size;
        });

        Measure("linq", () =>
        {
            long result = 0;
            for (int i = 0; i < RepeatCount; i++)
            {
                result = items.Sum();
            }
            return RepeatCount * Size;
        });

        Measure("linq 2", () =>
        {
            long result = 0;
            for (int i = 0; i < RepeatCount; i++)
            {
                result = enumerable.Aggregate(0L, (k, j) => k + j);
            }
            return RepeatCount * Size;
        });

        Console.Write("Done.");
        Console.ReadKey();
    }


    static void Measure(string name, Func<long> callback)
    {
        GC.Collect();
        GC.WaitForPendingFinalizers();
        GC.Collect();

        var mem = GC.GetTotalMemory(true);
        var gc = GC.CollectionCount(0);

        var sw = Stopwatch.StartNew();
        var result = callback();
        sw.Stop();

        var mem2 = GC.GetTotalMemory(false);
        var gc2 = GC.CollectionCount(0);

        var memDelta = (mem2 - mem) / 1024.0;
        var gcDelta = gc2 - gc;

        Console.WriteLine(
            "{0,14}: {1,5}ms, ips: {2,22:N} | Mem: {3,6:N2} kb, GC0: {4} => {5,6}",
            name, sw.ElapsedMilliseconds, result / sw.Elapsed.TotalSeconds, memDelta, gcDelta, result);
    }
}