Как насчет стандартной библиотеки, определенной в стандарте C ++?
1)
#include <map> // std::map, key-value pairs, unique keys
// also contains std::multimap, same as std::map, duplicate keys
// C++11 only:
#include <unordered_map> // std::unordered_map, key-value pairs, unique keys, hash table
// also contains std::unordered_multimap
2)
#include <sstream> // std::(i|o)stringstream, allow conversion from / to different data types
// C++11 only:
#include <string> // std::to_string for arithmetic types to strings (int, double, etc)
// std::stoi, std::stol, etc for strings to arithmetic types
// Boost library
#include <boost/lexical_cast.hpp> // boost::lexical_cast for conversions similar to stringstreams
3)
// C standard library, part of C++ standard library
#include <ctime> // std::time, std::gmtime, std::localtime