template<typename _MapType>
auto get_map_key_value(const _MapType& input_map, const decltype(input_map.begin()->second)& mapped_value) -> decltype(input_map.begin()->first)
{
auto iter = std::find_if(input_map.begin(), input_map.end(), [mapped_value](const auto& item) {
return (item.second == mapped_value);
});
if (iter == input_map.end())
{
return decltype(input_map.begin()->first)();
}
return iter->first;
}
int main()
{
std::map<int, std::string> open_status_map{
{ 3, "open" },
{ 4, "close" }
};
int i_open = get_map_key_value(open_status_map, "open");
return 0;
}
