using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

namespace HelloWorld

{

    class Program

    {

​

​

        public static string Reverse(string str)

        {

            return string.Join(",", str.Split(',').Select(x => new String(x.Reverse().ToArray())));

        }

​

        static public string Reverse2(string str)

        {

            StringBuilder reversed = new StringBuilder();

​

            foreach (var word in str.Split(','))

            {

                char[] singlesentence = word.ToCharArray();

                Array.Reverse(singlesentence);

                reversed.Append(singlesentence);

                reversed.Append(",");

            }

            return reversed.ToString().TrimEnd(',');

        }

​

​

​

        static void Perform(Func<string, string> Function, string names, int iterations, string type)

        {

​

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

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

                Function(names);

​

            watch.Stop();

​

            var elapsed = watch.ElapsedMilliseconds;

            Console.WriteLine($"Time taken for {type}: {elapsed} ms");

        }

​

​

        static void Main()

        {

            string names = String.Join(",",from x in Enumerable.Range(0, 100000) select "jack");

            const int iterations = 10;

            Perform(Reverse, names, iterations, "Join: ");

            Perform(Reverse2, names, iterations, "StringBuilder: ");

        }

​

    }

​

}

​