Binary Search In C#

using System;

namespace BinarySearch

{

    class Program

    {

        public static void Main()

        {                                

            int[] array = new int[10] { 13, 16, 17, 18, 2, 4, 7, 8, 9, 11  };

            Array.Sort(array);

            Console.WriteLine("Enter Search element");            

            string readLine = Console.ReadLine();

            int SearchKey = Int32.Parse(readLine);

            int low = 0;

            int high = array.Length - 1;

            while (low <= high)

            {

                int midPos = (low + high) / 2;

                if (SearchKey < array[midPos])

                    high = midPos - 1;

                else if (SearchKey > array[midPos])

                    low = midPos + 1;

                else if (SearchKey == array[midPos])

                {                    

                    Console.WriteLine("Search successful");                   

                    Console.WriteLine("Element {0} found at location {1}\n",

                                         SearchKey, midPos + 1);

                    return;

                }

            }

            Console.WriteLine("Search Unsuccessful");

        }

    }

}



Recursive Ways

public static object BinarySearchRecursive(int[] inputArray,

                            int SearchKey, int min, int max)

{

   if (min > max)

   {

       return "Nil";

   }

   else

   {

       int midPos = (min + max) / 2;

       if (SearchKey == inputArray[mid])

       {

           return ++midPos;

       }

       else if (SearchKey < inputArray[midPos])

       {

           return BinarySearchRecursive(inputArray, SearchKey, min, midPos - 1);

       }

       else

       {

           return BinarySearchRecursive(inputArray, SearchKey, midPos + 1, max);

       }

   }

}