PAT1002 写出这个数 int《=》string

#include <iostream>
#include<stdio.h>
#include<string>
#include<sstream>
using namespace std;
string int_to_string(int n)
{
ostringstream stream;
stream<<n;
return stream.str();
}
int main()
{
int sum=0;
char ch;
string ss;
string b[10]={"ling", "yi", "er", "san", "si", "wu", "liu", "qi", "ba", "jiu"};
while ((ch = getchar()) != '\n')    //如果一直输入字符，不按回车的话
sum += (ch - '0');//string to int
ss=int_to_string(sum);
for (int i=0;i<ss.length();i++)
{
if(i==ss.length()-1)
cout<<b[ss[i]-'0'];
else
cout<<b[ss[i]-'0']<<" ";
}
return 0;
}