二分查找法(仅供个人拾遗)

 private static void Main(string[] args)
        {
            int[] data = new int[10];

            for (int i = 0; i < 10; i++)
            {
                data[i] = i + 3;
            }


            for (int i = 0; i < 10; i++)
            {
                Console.Write(data[i] + " ");
            }
            Console.WriteLine();
            int ii = BinarySearch.Search(data, 9);
            Console.WriteLine(ii);
        }

public static class BinarySearch
    {
        public static int  Search(int[] data,int val)
        {
            // if data is null ,return -1
            if (data.Length <= 0)
            {
                return -1;
            }
            int low = 0;
            int high = data.Length - 1;
            while (low <= high)
            {
                int middle = (low + high) / 2;
                if (data[middle] == val)
                { 
                    return middle; 
                }
                else if (data[middle] <val)
                {
                    low = middle + 1;
                }
                else
                {
                    high = middle - 1;
                }
            }
            return -1;
        }
    }