Bynary Search

//11. Write a program that finds the index of given element in a
//sorted array of integers by using the binary search algorithm (find it in Wikipedia).
using System;

class Program
{
    static void Main()
    {
        int[] arr = { -8, -6, -1, 2, 3, 4, 6, 8 }; // arr ---- >
        int searched =-8;
        int decreaceInd = 0;
        int increaceInd = arr.Length - 1;
        int midIndex = 0;
        int midlElValue = int.MinValue;

        int left = int.MinValue;
        int right = int.MaxValue;

        while (midlElValue != searched)
        {
            midIndex = (decreaceInd + increaceInd) / 2; // arr[decrInd---?--mid index ---?--incrInd>>>]
                                             //decreaceInd = decreaceInd + (increaceInd) / 2;
            midlElValue = arr[midIndex];
            if (midlElValue > searched) // arr[----?--------mid index----->]
            {                               // so search in <--- this direction  use
                increaceInd = midIndex-1;// -1 to start from next index

                right = arr[increaceInd]; // bonus

            }                           // arr[ decrId(same) ------?---mid Index----incrInd(midIndex-1)>>>>]
            if (midlElValue < searched)// arr[--------mid index---?----->]
            {                            //arr[ decrId(midIndex+1) ------?---mid Index----incrInd(same)>>>>]
                decreaceInd = midIndex + 1;

                left = arr[decreaceInd];//bonus
            }

            if (left < searched && searched > right)
            {
                Console.WriteLine("value {0} not amember in arr",searched);
            }
        }
        Console.WriteLine("Searched El {0}  index in arr [{1}]", searched, midIndex);

    }
}