数字大小写转换

public static string RevertNumToBig(int num)
{
string bigNum = string.Empty, bigNumPart = string.Empty;
//int g = 0, s = 0, b = 0, q = 0, w = 0;
string[] bigNumArr = new string[] { "零", "一", "二", "三", "四", "五", "六", "七", "八", "九", "十" };
string[] levels = new string[] { "", "十", "百", "千", "万", "亿" };
int pow = 0, lvNum = 0;
while ((double)num >= System.Math.Pow(10, pow))
{ pow++; }

while (pow > 0)
{
if (num > 0 || pow > 4)
{//末位为零时不显示
lvNum = num / (int)(System.Math.Pow(10, pow - 1));
if (lvNum > 0 || (pow < 8 && !bigNum.EndsWith("零")))//去除多余显示的'零'
bigNum += bigNumArr[lvNum];

if (pow > 4 && pow % 4 == 1)
{
if (!bigNum.EndsWith("亿"))//当万级都为0时跳过
bigNum += levels[pow % 4 + 4 - pow / 4 % 2];//每4位获得最大的数量级
}
else
{
if (lvNum > 0)
bigNum += levels[(pow % 4 == 0) ? 3 : (pow % 4 - 1)];//获得每位的数量级
}
}
num -= (int)(System.Math.Pow(10, pow - 1)) * lvNum;//减去已计算的位数
pow--;
}
if (bigNum.Contains("亿零万"))
bigNum = bigNum.Replace("零万", string.Empty);
else if (bigNum.Contains("零万"))
bigNum = bigNum.Replace("零万", "万");
return bigNum;
}