Implement Binary Search in C# dotnet

  class BinartSearch  
   {  
     public static int BinarySearch(int key, int[] arr)  
     {  
       int low = 0;  
       int high = arr.Length - 1;  
       int middle;  
       while (low <= high)  
       {  
         middle = (low + high) / 2;  
         if (key > arr[middle])  
           low = middle + 1;  
         else if (key < arr[middle])  
           high = middle - 1;  
         else  
           return middle;  
       }  
       return -1;  
     }  
     public static void PrintArray(int low, int middle, int high, int[] arr)  
     {  
       for (int i = 0; i <= high; i++)  
       {  
         if (i < low)  
         {  
           Console.Write("  ");  
         }  
         else  
         {  
           if (i == middle)  
             Console.Write("{0,2}m ", arr[i]);  
           else  
             Console.Write("{0,2} ", arr[i]);  
         }  
       }  
       Console.WriteLine();  
     }  
     public static void Main()  
     {  
       int searchKey;  
       int searchResult;  
       int[] testScores = { 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38 };  
       do  
       {  
         Console.Write("Please enter the test score you would like to locate: ");  
         searchKey = Convert.ToInt32(Console.ReadLine());  
         searchResult = BinarySearch(searchKey, testScores);  
         if (searchResult >= 0)  
           Console.WriteLine("The score was found in position: {0}\n", searchResult);  
         else  
           Console.WriteLine("The score was not found\n");  
         Console.Write("Would you like to do another search? Y)es N)o ");  
       } while (Console.ReadLine().ToUpper() == "Y");  
     }  
   }