STL map, multimap, and set

[hopesfall]

What do the map and set classes in the STL do? What do they have in common and how are they different?

I came across the multimap class also and was wondering what the difference between it and the map class is? Is it just that the multimap class allows duplicate key values?

[clanmjc]

In Short: They are all associative containers. They are efficient at look up by their keys.

Maps have <key, values> where the keys are unique.
map - http://www.cplusplus.com/reference/stl/map/

Multimap have <key value, values> where more than one value can map to a key value.
multimap - http://www.cplusplus.com/reference/stl/multimap/

Sets are <key> where the elements are the keys themselves and are unique.
set - http://www.cplusplus.com/reference/stl/set/

[hopesfall]

Thank you so much