You need to duplicate every third word in the entered C++ string. How can I fix my current code?

Question

C++ / C#

wstring s, a, b;
getline(ws(wcin), s);
int k = 0;
int slovo, count = 0;
 
int i = 0;
while (s[i] == ' ' && s[i] != '\0')
    i++;
slovo = 0;
while (s[i] != '\0') {
    if (s[i] != ' ' && slovo == 0)
    {
        slovo = 1;
        count++;
        if (count%3==0) 
        {
           
            int pos = i + 1;
            while (iswspace(s[pos])) pos--;
            while (!iswspace(s[pos])) pos--;
 
            int len = abs(pos - i);
            if (s[i + 1] == '\0') len++;
 
            while (--len >= 0)
            {
                for (int q = pos; s[q] != '\0'; q++)
                    a += s[q];
                b += L"" + a;
                s.insert(i - 1 , L"" + a);
                i += a.length() + 1;
                a = L"";
                count = 0;
            }
        }
    }
    else if (s[i] == ' ')
        slovo = 0;
    i++;
}
wcout << L"\nРезультат: ";
 
wcout << s;

Please help me improve the code, given that the string can contain any characters other than line breaks, including spaces and tabs.

Answer 1

Here's what I wrote quickly for your problem:

#include <iostream>
#include <string>
#include <sstream>

int main() {
      std::string str;
      std::cout << "Enter string: ";
      std::getline(std::cin, str);
      std::stringstream s(str);
      std::string tmp, res;
      int count = 0;
      while(s >> tmp) {
             res += tmp + ' ';
             ++count;
             if(count%3==0) res += tmp + ' ';
      }
      res = res.substr(0, res.length()-1);
      std::cout<<res;
      return 0;
}