C# 人民币大写金额转换

/// <summary> 
     /// 转换人民币大小金额 
     /// </summary> 
     /// <param name="num">金额</param> 
     /// <returns>返回大写形式</returns> 
     public static string cmycurd(decimal num)
     {
         string str1 = "零壹贰叁肆伍陆柒捌玖";            //0-9所对应的汉字 
         string str2 = "万仟佰拾亿仟佰拾万仟佰拾元角分"; //数字位所对应的汉字 
         string str3 = "";    //从原num值中取出的值 
         string str4 = "";    //数字的字符串形式 
         string str5 = "";  //人民币大写金额形式 
         int i;    //循环变量 
         int j;    //num的值乘以100的字符串长度 
         string ch1 = "";    //数字的汉语读法 
         string ch2 = "";    //数字位的汉字读法 
         int nzero = 0;  //用来计算连续的零值是几个 
         int temp;            //从原num值中取出的值 
 
         num = math.round(math.abs(num), 2);    //将num取绝对值并四舍五入取2位小数 
         str4 = ((long)(num * 100)).tostring();        //将num乘100并转换成字符串形式 
         j = str4.length;      //找出最高位 
         if (j > 15) { return "溢出"; }
         str2 = str2.substring(15 - j);   //取出对应位数的str2的值。如：200.55,j为5所以str2=佰拾元角分 
 
         //循环取出每一位需要转换的值 
         for (i = 0; i < j; i++)
         {
             str3 = str4.substring(i, 1);          //取出需转换的某一位的值 
             temp = convert.toint32(str3);      //转换为数字 
             if (i != (j - 3) && i != (j - 7) && i != (j - 11) && i != (j - 15))
             {
                 //当所取位数不为元、万、亿、万亿上的数字时 
                 if (str3 == "0")
                 {
                     ch1 = "";
                     ch2 = "";
                     nzero = nzero + 1;
                 }
                 else
                 {
                     if (str3 != "0" && nzero != 0)
                     {
                         ch1 = "零" + str1.substring(temp * 1, 1);
                         ch2 = str2.substring(i, 1);
                         nzero = 0;
                     }
                     else
                     {
                         ch1 = str1.substring(temp * 1, 1);
                         ch2 = str2.substring(i, 1);
                         nzero = 0;
                     }
                 }
             }
             else
             {
                 //该位是万亿，亿，万，元位等关键位 
                 if (str3 != "0" && nzero != 0)
                 {
                     ch1 = "零" + str1.substring(temp * 1, 1);
                     ch2 = str2.substring(i, 1);
                     nzero = 0;
                 }
                 else
                 {
                     if (str3 != "0" && nzero == 0)
                     {
                         ch1 = str1.substring(temp * 1, 1);
                         ch2 = str2.substring(i, 1);
                         nzero = 0;
                     }
                     else
                     {
                         if (str3 == "0" && nzero >= 3)
                         {
                             ch1 = "";
                             ch2 = "";
                             nzero = nzero + 1;
                         }
                         else
                         {
                             if (j >= 11)
                             {
                                 ch1 = "";
                                 nzero = nzero + 1;
                             }
                             else
                             {
                                 ch1 = "";
                                 ch2 = str2.substring(i, 1);
                                 nzero = nzero + 1;
                             }
                         }
                     }
                 }
             }
             if (i == (j - 11) || i == (j - 3))
             {
                 //如果该位是亿位或元位，则必须写上 
                 ch2 = str2.substring(i, 1);
             }
             str5 = str5 + ch1 + ch2;
 
             if (i == j - 1 && str3 == "0")
             {
                 //最后一位（分）为0时，加上“整” 
                 str5 = str5 + '整';
             }
         }
         if (num == 0)
         {
             str5 = "零元整";
         }
         return str5;
     }