Some STL containers, such as std::map, are designed to use std::pair to maintain keys and values. A special convenience function, std::make_pair, is often used to create pairs without having to specify template argument types. Typical code that makes use of an STL map looks like this:

std::map<std::string, std::string> m;		// map<key,value>
m.insert(std::make_pair("1", "one"));
m.insert(std::make_pair("2", "two"));
printf("%s", m.find("1")->second.c_str());	// prints "one"