binary_search

namespace binary_search
{
    internal class Program
    {

        static void Main(string[] args)
        {
            int[] array = new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 };
            int target = 8;


            int itterativePos = ItterativeBinarySearch(array, target);
            Console.WriteLine(itterativePos);

            int recursivePos = RecursiveBinarySearch(array, target);
            Console.WriteLine(recursivePos);
        }

        private static int RecursiveBinarySearch(int[] array, int target)
        {
            int l = 0, r = array.Length - 1;

            return RecursiveBinarySearch(array, target, l, r);
        }

        private static int RecursiveBinarySearch(int[] array, int target, int l, int r)
        {
            int m = (l + r) / 2;

            if (l > r)
            {
                return -1;
            }

            if (array[m] == target)
            {
                return m;
            }
            if (array[m] > target)
            {
                r = --m;
            }
            if (array[m] < target)
            {
                l = ++m;
            }

            return RecursiveBinarySearch(array, target, l, r);
        }

        private static int ItterativeBinarySearch(int[] array, int target)
        {
            int l = 0, r = array.Length - 1;

            while (l <= r)
            {
                int m = (l + r) / 2;

                if (array[m] == target)
                {
                    return m;
                }

                else if (array[m] > target)
                {
                    r = --m;
                }
                else// if (array[m] < target)
                {
                    l = ++m;
                }
            }

            return -1;
        }

    }
}