Reverse a string and Sentence without inbuilt functions

1. Reversing a sentence without reversing the words



using System;

namespace ReverseSentense
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Write the sentence to reverse");
            string input = Console.ReadLine();

            string[] sentense = input.Split(' ');
            string output = "";
            for (int i = sentense.Length - 1; i >= 0; i--)
            {
                if (!string.IsNullOrEmpty(output))
                    output = output + " ";

                output = output + sentense[i];
            }
            Console.WriteLine(output);
            Console.ReadKey();
        }
    }
}

output :

2. Reversing a sentence with reversing the words in it.



using System;

namespace ReverseStringSentense
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Enter the string to reverse");
            string input = Console.ReadLine();

            string[] sentense = input.Split(' ');
            string output = string.Empty;
            string temp = string.Empty;

            for (int i = sentense.Length - 1; i >= 0; i--)
            {
                string s = sentense[i];
                temp = string.Empty;
                for (int j = s.Length - 1; j >= 0; j--)
                {
                    temp = temp + s[j];
                }  
                output = output +" "+ temp;
            }
            Console.WriteLine(output.TrimStart());
            Console.ReadKey();
        }
    }
}

output : 
         

      

3. Reversing a string alone with and without using inbuilt functions:



using System;

namespace ReversEntireString
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Enter the srtring to reverse");
            string input = Console.ReadLine();
           
            string output = "";

            //foreach (char a in input.Reverse().ToArray())
            //{
            //    output = output + a;
            //}
           

            for (int i = input.Length-1; i >= 0; i--)
            {
                output = output + input[i];
            }
            Console.WriteLine(output);
            Console.ReadLine();

        }
    }
}

Output :