STL’s Associative Containers
All of the STL containers you have seen so far have stored individual data elements. In this chapter you will be introduced to associative containers. These containers associate a key with the data values that you are inserting. In the case of the map and unordered_map containers, you are required to supply a value to use as the key, whereas the set and unordered_set containers automatically generate keys from the data you supply. I'll explain the differences between each of these containers as I work through some examples in this chapter, beginningwith the set container.