using System;

using System.Diagnostics;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        string str = "Hello";

        var timer1 = new Stopwatch();

        var timer2 = new Stopwatch();

        timer1.Start();

        ReverseAString_1(str);

        timer1.Stop();

        TimeSpan timeTaken = timer1.Elapsed;//.ElapsedMilliseconds;

        string tt = timeTaken.ToString(@"m\:ss\.fff");

        //Console.WriteLine($"The Time taken for Method-1 is {timeTaken.ToString(@'m\:ss\.fff')}");

        Console.WriteLine($"The Time taken for Method-1 is {tt}");

        Console.WriteLine($"The Time taken for Method-1 is {timer1.ElapsedMilliseconds}");

        timer2.Start();

        ReverseAString_2("Hello World");

        timer2.Stop();

        TimeSpan timeTaken2 = timer1.Elapsed;//.ElapsedMilliseconds;        

        Console.WriteLine($"The Time taken for Method-2 is {timer2.ElapsedMilliseconds}");

        string str3 = "Hello World, This is Rocky";

        string str3_new = ReverseWords(str3);

        Console.WriteLine($"The Original string is {str3}");

        Console.WriteLine($"The Reversed string is {str3_new}");

    }

    static void ReverseAString_1(string str)

    {

        char[] charArray = str.ToCharArray();

        int leftPointer=0, rightPointer=str.Length-1;

        char tmp = new char();

        while(leftPointer < rightPointer)

        {

            tmp = charArray[leftPointer];

            charArray[leftPointer] = charArray[rightPointer];

            charArray[rightPointer] = tmp;

            leftPointer++;

            rightPointer--;

        }

        Console.WriteLine($"The Original string is {str}");

        Console.WriteLine($"The Reversed string is {new string(charArray)}");

    /* linq

      string str4 = "Hello World";

      string res = string.Join(" ", str4.Split(' ').Select(s => new String(s.Reverse().ToArray())));

      Console.WriteLine(res);

      */

    }

    static void ReverseAString_2(string str)

    {

        char[] charArray = str.ToCharArray();

        char[] charArray_new = new char[charArray.Length];

        int counter=charArray.Length-1;

        for(int i=0; i< charArray.Length-1; i++)

        {

            charArray_new[i] = charArray[counter];

            counter--;

        }   

        Console.WriteLine($"The Original string is {str}");

        Console.WriteLine($"The Reversed string is {new string(charArray_new)}");

    }

    static string ReverseWords(string input)

    {

        string[] words = input.Split(' ');

        //string[] words = input.Split(new char[]{' ',','});

        for (int i = 0; i < words.Length; i++)

        {

            words[i] = ReverseString(words[i]);

        }

        return string.Join(" ", words);

    }

    static string ReverseString(string s)

    {

        char[] charArray = s.ToCharArray();

        Array.Reverse(charArray);

        return new string(charArray);

    }

}