private static string BigNumberPow(int baseNumber, int power)        {// Math.Log10(x^y) = y * Math.Log10(x).// 估计结果有多少位。            double rawDigitCount = power * Math.Log10((double)baseNumber);double digitCount = (int)(Math.Ceiling(rawDigitCount));// 这里用万进制，即满一万进1，运算过程用数组来存放，数组中每一个的最大值是9999。// 除以4，得到所需的数组的长度。            int arrayLength = (int)(Math.Ceiling((double)(digitCount / 4.0)));

int[] numbers = new int[arrayLength];int jinweinumber = 0;// 模拟人工运算，设置初始值。            numbers[arrayLength - 1] = baseNumber;// 由于设置了初始值，所以需要乘以baseNumber共power -1次。            for (int j = 1; j < power; j++)            {// 对每一段乘以baseNumber,注意进位的值要加到前一段。                for (int i = arrayLength - 1; i >= 0; i--)                {if (numbers[i] == 0 && jinweinumber == 0)continue;                    numbers[i] = numbers[i] * baseNumber;                    numbers[i] += jinweinumber;if (numbers[i] > 9999)                    {                        var quyu = numbers[i] % 10000;                        jinweinumber = (numbers[i] - quyu) / 10000;                        numbers[i] = quyu;                    }else                        jinweinumber = 0;                }            }

            StringBuilder result = new StringBuilder();for (int i = 0; i < arrayLength; i++)            {// 不足四位的前面补0。                result.Append(numbers[i].ToString("0000"));            }

return result.ToString().TrimStart('0');        }

private static string JieCh(int n)        {// 使用万进制，每个数组元素四位，估计用来存计算结果所需数组的长度。            int arraylength = 50;int[] numbers = new int[arraylength];            numbers[arraylength - 1] = 1;for (int j = 2; j <= n; j++)            {int jinweinumber = 0;for (int i = arraylength - 1; i >= 0; i--)                {                    numbers[i] *= j;                    numbers[i] += jinweinumber;if (numbers[i] > 9999)                    {                        var quyu = numbers[i] % 10000;                        jinweinumber = (numbers[i] - quyu) / 10000;                        numbers[i] = quyu;                    }else                        jinweinumber = 0;                }            }            StringBuilder result = new StringBuilder();for (int i = 0; i < arraylength; i++)            {                result.Append(numbers[i].ToString("0000"));            }

return result.ToString().TrimStart('0');        }