The missing std::string::replace_all(str, from, to)

std::string::replace_all.cpp

size_t replace_all(string &str, const string &from, const string &to) {
  size_t count = 0;
  
  size_t pos = 0;
  while ((pos = str.find(from, pos)) != string:npos) {
    str.replace(pos, from.length(), to);
    pos += to.length();
    ++count;
  }
  
  return count;
}