using System;

public class Program

{

    public static void Main()

    {

        StringBuilderTest();

        //StringConcatTest();

    }

    public static void StringBuilderTest()

    {

        var str = new System.Text.StringBuilder();

        str.Append("hello");

        var stopwatch = System.Diagnostics.Stopwatch.StartNew();

        for(int i = 0; i < 1000; i++)

        {

            str.Append("world");            

        }

        Console.WriteLine("Execution took: " + stopwatch.ElapsedMilliseconds);

    }

    public static void StringConcatTest()

    {

        var str = "hello";

        var stopwatch = System.Diagnostics.Stopwatch.StartNew();

        for(int i = 0; i < 1000; i++)

        {

            str = str + "world";            

        }

        Console.WriteLine("Execution took: " + stopwatch.ElapsedMilliseconds);

​

    }

}