开方算法，请高人指点

昨天听朋友说去面试人家考了开方的算法，我就自己写了一个，自知效率不高，有情高人给指点一二。不胜感激static class Program
    {
        public static double i = 0;
        static void Main()
        {
            Sqra(1.0, 1);
            Console.ReadLine();
        }
        public static void Sqra(double number, double jump)
        {
            if (jump < 0.0000001)
            {
                Console.WriteLine(i.ToString());
                return;
            }
            bool isWhile = true;
            while (isWhile)
            {
                if (i * i == number)
                {
                    isWhile = false;
                    Console.WriteLine(i.ToString());
                }
                if (i * i > number)
                {
                    isWhile = false;
                    i -= jump;
                    Sqra(number, jump/10);
                }
                i += jump;
            }        }