The STL has both container concepts and container types. The concepts are general categories with names such as container, sequence container, and associative container. The container types are templates you can use to create specific container objects. The original 11 container types are
bitset. (This chapter doesn’t discuss
bitset, which is a container for dealing with data at the bit level.) C++11 adds
unordered_multiset, and it moves
bitset from the container category into its own separate category. Because the concepts categorize the types, let’s start with them.