朋友遇到一个面试题 转换人民币

string num = "零一二三四五六七八九";            string unit = "千百十万千百十亿千百十万千百十元角分里";            do            {                try                {                    Console.WriteLine("输入转换");                    double d = Convert.ToDouble(Console.ReadLine());                    string str = d.ToString("0000000000000000.000");                    str = str.Remove(str.IndexOf('.'), 1);                    StringBuilder sb = new StringBuilder();                    for (int i = 0; i < str.Length; i++)                    {                        if (str[i] != '0')                        {                            Console.WriteLine(str[i]);                            sb.Append(num[str[i] - 48]);                            //sb.Append(num[str[i] - '0']);                            sb.Append(unit[i]);                        }                        else if (i > 0 && str[i - 1] != '0')                        {                            sb.Append(num[str[i] - 48]);                            //sb.Append(num[str[i] - '0']);                        }                    }                    Console.WriteLine(sb.ToString().Trim('零'));                }                catch (Exception e) { Console.WriteLine(e.Message); }            } while (true);