binary search (or binary chop) o(log n) is a Logarithmic algorithm. Doubling the data only means it needs to do one extra chop.

BinarySearch.cs

using System;
using System.Linq;

namespace CsharpCodeExamples
{
    class Program
    {

        static void Main(string[] args)
        {
            // binary search (or binary chop) o(log n) is a Logarithmic algorithm.   
            // Doubling the data only means it needs to do one extra chop.

            int[] data = Enumerable
                .Range(0, 120).ToArray();

            int find = 11;
            int length = data.Length;
            Console.WriteLine(string.Format("Array contains '{0}' items.", data.Length - 1));

            int low = 0;
            int high = data.Length - 1;
            var checkCnt = 0;
            while (low <= high)
            {
                checkCnt++;
                var mid = (low + high) / 2;
                if (find == data[mid])
                {
                    Console.WriteLine(string.Format("{0} can be found at number '{1}'", find, mid));
                    break;
                }
                else if (find < data[mid])
                    high = mid - 1;
                else
                    low = mid + 1;
            }
            Console.WriteLine(string.Format("I preformed '{0}' checks", checkCnt));
            Console.ReadLine();

        }
    }
}