PAT (Basic Level) Practice （中文）1002 写出这个数 (20 分)

终于步入20分的题啦，本题在最后输出无法回退掉那个空格， 试过cout<<’\b’<<endl;但是不行，如果有大佬看见了给讲讲怎么不区分最后一个，直接回退掉那个空格。下面是完整的代码

#include<iostream>
#include<string>
#include<math.h>
using namespace std;
int main() {
 int sum = 0;
 string s;
 cin >> s;
 for (int i = 0; i < s.length(); i++) {
  sum = sum + s[i] - '0';
 }
 s = to_string(sum);
 for (int i = 0; i < s.length()-1; i++) {
  switch (s[i]) {
  case '0':cout << "ling" << " "; break;
  case '1':cout << "yi" << " "; break;
  case '2':cout << "er" << " "; break;
  case '3':cout << "san" << " "; break;
  case '4':cout << "si" << " "; break;
  case '5':cout << "wu" << " "; break;
  case '6':cout << "liu" << " "; break;
  case '7':cout << "qi" << " "; break;
  case '8':cout << "ba" << " "; break;
  case '9':cout << "jiu" << " "; break;
  }
 }
 switch (s[s.length()-1]) {
 case '0':cout << "ling" ; break;
 case '1':cout << "yi" ; break;
 case '2':cout << "er" ; break;
 case '3':cout << "san" ; break;
 case '4':cout << "si" ; break;
 case '5':cout << "wu" ; break;
 case '6':cout << "liu" ; break;
 case '7':cout << "qi" ; break;
 case '8':cout << "ba" ; break;
 case '9':cout << "jiu" ; break;
 }
 return 0;
}