using System;

using System.Diagnostics;

using System.Text;

public class Program

{

    private static Stopwatch _watch = new Stopwatch();

    public static void Main()

    {

        for(double times = 0; times <= 1000; times *= 10)

        {

            var stringTestResult = Test(() => StringTest((int)times));

            var stringBuilderTestResult = Test(() => StringBuilderTest((int)times));

            var stringBuilderPresetTestResult = Test(() => StringBuilderPresetTest((int)times));

            if(times == 0) {times=0.1;continue;} // first time is warming up, doesn't count

            Console.WriteLine($"Testing against {times} times concatenation.");

            Console.WriteLine($"String: {stringTestResult}");

            Console.WriteLine($"StringBuilder: {stringBuilderTestResult}");

            Console.WriteLine($"StringBuilderPreset: {stringBuilderPresetTestResult}");

            Console.WriteLine();

        }

    }

    public static long Test(Action test)

    {

        _watch.Restart();

        for(var x =0; x<=100; x++) test();

        _watch.Stop();

        var ticks = _watch.ElapsedTicks;        

        return ticks;

    }

​

    public static void StringTest(int times)

    {

        var s = string.Empty;           

        for(var x = 0; x < times; x++)

            s += ' ';

        s = string.Empty;

    }

​

    public static void StringBuilderTest(int times)

    {

        var s = new StringBuilder();

        for(var x = 0; x < times; x++)

            s.Append(' ');

        s.Clear();

    }

​

    public static void StringBuilderPresetTest(int times)

    {

        var s = new StringBuilder(times);

        for(var x = 0; x < times; x++)

            s.Append(' ');

        s.Clear();

    }

}