PAT 1082. Read Number in Chinese

Given an integer with no more than 9 digits, you are supposed to read it in the traditional Chinese way. Output "Fu" first if it is negative. For example, -123456789 is read as "Fu yi Yi er Qian san Bai si Shi wu Wan liu Qian qi Bai ba Shi jiu". Note: zero ("ling") must be handled correctly according to the Chinese tradition. For example, 100800 is "yi Shi Wan ling ba Bai".

Input Specification:

Each input file contains one test case, which gives an integer with no more than 9 digits.

Output Specification:

For each test case, print in a line the Chinese way of reading the number. The characters are separated by a space and there must be no extra space at the end of the line.

Sample Input 1:

-123456789

Sample Output 1:

Fu yi Yi er Qian san Bai si Shi wu Wan liu Qian qi Bai ba Shi jiu

Sample Input 2:

100800

Sample Output 2:

yi Shi Wan ling ba Bai

#include<iostream>
using namespace std;
string form[10]={"ling","yi","er","san","si","wu","liu","qi","ba","jiu"};
int tag=0,cnt=0,flag=0;
void read(string s){
    for(int i=0;i<s.size();i++){
        int pos=s.size()-i;
        if(s[i]=='0'){
 // 遇到0的时候，记录flag=1，等下次碰到非零的数时候在输出ling，
 //   可以避免遇到1001时输出两个ling的情况             
            flag=1;
        }else{
            if(flag==1) cout<<" ling"; // 
            if(tag!=1) cout<<" "; //tag=1时，是开头不能输出空格 
            if(pos==4)
               cout<<form[s[i]-'0']<<" Qian";
            else if(pos==3)
               cout<<form[s[i]-'0']<<" Bai";
            else if(pos==2)
               cout<<form[s[i]-'0']<<" Shi";
            else 
               cout<<form[s[i]-'0'];
            flag=0; tag=0;
        }
    }
}
int main(){
    string num,s;
    cin>>num;
    if(num=="0") cout<<"ling"<<endl; // 特例：0 
    if(num[0]=='-'){
       cout<<"Fu "; // 处理负数 
       num=num.substr(1);
    }
    for(int i=0;i<num.size();i++){
        int pos=num.size()-i;
        if(pos==9){ // 九位数的情况 
           cout<<form[num[i]-'0']<<" Yi";
           cnt++;
        }
        else if(pos<=8&&pos>=5){ // 大于等于5位数的情况 
            if(i==0) tag=1;  //tag=1时，是开头不能输出空格 
            s=num.substr(i,num.size()-cnt-4);
            i+=num.size()-cnt-4-1;
            read(s);
            cnt+=s.size();
            cout<<" Wan";
        }else if(pos<=4&&pos>=1){ // 小于等于4位数的情况 
            if(i==0) tag=1;   //tag=1时，是开头不能输出空格 
            s=num.substr(i,num.size()-cnt);
            read(s);
            break;
        }
    }
    return 0; 
}