PAT 1082. Read Number in Chinese(25)

//已AC

//3 points not passed...是因爲‘0’

#include<iostream>
#include<cstring>
//#include<algorithm>
using namespace std;
char num[11];
char chinese_digit[10][5] = { "ling", "yi", "er", "san", "si", "wu", "liu", "qi", "ba", "jiu" };
char chinese_unit[10][5] = { "Yi", "Qian", "Bai", "Shi", "Wan", "Qian", "Bai", "Shi" };
bool first = true;
int main(){
 cin.getline(num, 11);
 int len = strlen(num);
 if (num[0] == '-'){
  cout << "Fu";
  for (int i = 0; i < len; i++){
   num[i] = num[i + 1];
  }
  len--;
  first = false;
 } 
 if (num[0] == '0'){
  cout << "ling"; return 0;
 }
 int i = 9;
 while (i > 0){
  if ((len - i) >= 0){
   if (num[len - i] != '0'){
    if (!first){
     cout << " " << chinese_digit[num[len - i] - '0'];
    }
    else{
     cout << chinese_digit[num[len - i] - '0'];
     first = false;
    }     
    if (9 - i < 8){
     cout << " " << chinese_unit[9 - i];
    }   
   }
   else{
    if (isdigit(num[len - i + 1]) && num[len - i + 1] != '0'&&i != 5)
     cout << " " << chinese_digit[num[len - i] - '0'];
    if (i == 5)
     cout << " Wan";
   }
  }
  --i;
  if (i <= 4)
   break;
 }
 while (i > 0){
  if ((len - i) >= 0){
   if (num[len - i] != '0'){
    if (!first){
     cout << " " << chinese_digit[num[len - i] - '0'];
    }
    else{
     cout << chinese_digit[num[len - i] - '0'];
     first = false;
    }
    if (9 - i < 8){
     cout << " " << chinese_unit[9 - i];
    }
   }
   else{
    if (isdigit(num[len - i + 1]) && num[len - i + 1] != '0')
     cout << " " << chinese_digit[num[len - i] - '0'];
   }
  }
  --i;
 }
}