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 is a data type for grouping two values together as a single object. std::map uses it for key, value pairs.

While you're learning pair, you might check out tuple. It's like pair but for grouping an arbitrary number of values. tuple is part of TR1 and many compilers already include it with their Standard Library implementations.

Also, checkout Chapter 1, "Tuples," of the book The C++ Standard Library Extensions: A Tutorial and Reference by Pete Becker, ISBN-13: 9780321412997, for a thorough explanation.