daneil1

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

using namespace std;

string process(const string& filename)
{
  ostringstream os;
  if(ifstream ifs(filename); ifs)
  {
    string line;
    while(getline(ifs, line))
    {
      if(auto pos = line.find("link"); pos != string::npos)
      {
        pos = line.find('\"', pos);
        auto end = line.find('\"', pos + 1);
        os << process(line.substr(pos + 1, end - pos - 1));
        continue;
      }
      os << line << "\n";
    }
  }
  return os.str();
}

int main()
{
  cout << process("text.txt");
  cin.get();
}