c++ map getting key from value code example

Example 1: c++ get map keys

template<typename TK, typename TV>
std::vector<TK> extract_keys(std::map<TK, TV> const& input_map) {
  std::vector<TK> retval;
  for (auto const& element : input_map) {
    retval.push_back(element.first);
  }
  return retval;
}

Example 2: get map values c++

template<typename TK, typename TV>
std::vector<TV> extract_values(std::map<TK, TV> const& input_map) {
  std::vector<TV> retval;
  for (auto const& element : input_map) {
    retval.push_back(element.second);
  }
  return retval;
}