What is std::pair?

Question

What is std::pair for, why would I use it, and what benefits does boost::compressed_pair bring?

Answer 1

std::pair comes in handy for a couple of the other container classes in the STL.

For example:

std::map<>
std::multimap<> 

Both store std::pairs of keys and values.

When using the map and multimap, you often access the elements using a pointer to a pair.