Map (C++) Design Characteristics Key uniqueness: in map and set each key must be unique. multimap and multiset do not have this restriction.Element composition: in map and multimap each element is composed from a key and a mapped value.
In set and multiset each element is key; there are no mapped values.Element ordering: elements follow a strict weak ordering Loop through map and print all the key/value pair : map iterator « Map Multimap « C++ STL Tutorial - Map Class. Suppose that you're working with some data that has values associated with strings -- for instance, you might have student usernames and you want to assign them grades.
How would you go about storing this in C++? One option would be to write your own hash table. This will require writing a hash function and handling collisions, and lots of testing to make sure you got it right. Map.