c++ std::map get keys 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: std::map get all keys

std::map<int, int> m;
std::vector<int> key, value;
for(std::map<int,int>::iterator it = m.begin(); it != m.end(); ++it) {
  key.push_back(it->first);
  value.push_back(it->second);
  std::cout << "Key: " << it->first << std::endl();
  std::cout << "Value: " << it->second << std::endl();
}