class Program { static void Main(string[] args) { #region 6、求一个数的偶数位的乘积(个位、百位、万位、百万位 等等 注:不允许操作字符串)。 // 个位、十位、百位、千位、万位、十万位、百万位 float num = 0; while (true) { Console.WriteLine("请输入任意一个4位数以上的正整数:"); num = float.Parse(Console.ReadLine()); if (num >= 1000) { break; } } if (1000 <= num && num < 100000) { int shiwei = GetNum(num, 0); int qianwei = GetNum(num, 1); Console.WriteLine("结果是:{0}", shiwei * qianwei); } else if (100000 <= num && num < 10000000) { int shiwei = GetNum(num, 0); int qianwei = GetNum(num, 1); int shiwanwei = GetNum(num, 2); Console.WriteLine("结果是:{0}", shiwei * qianwei * shiwanwei); } else { int shiwei = GetNum(num, 0); int qianwei = GetNum(num, 1); int shiwanwei = GetNum(num, 2); int qianwanwei = GetNum(num, 3); Console.WriteLine("结果是:{0}", shiwei * qianwei * shiwanwei * qianwanwei); } Console.ReadLine(); #endregion } public static int GetNum(float num, int i) { int result = 0; int wei = 1; if (i == 0) { wei = 100; } if (i == 1) { wei = 10000; } if (i == 2) { wei = 1000000; } if (i == 3) { wei = 100000000; } float c = num / wei; int a = (int)(c); float b = c - a; result = (int)(b * 10); return result; } }