C++11: Multimap vs Map

What is the difference between a multimap and a map in C++11?

In C++11, a map is a collection of key-value pairs where each key is unique, while a multimap allows duplicate keys.

Can you give an example of when to use a multimap?

Use a multimap when you need to store multiple values for the same key, like storing students' grades by subject.

Are there any performance differences between them?

Yes, maps generally have faster lookups due to unique keys, while multimaps may have slower lookups because of potential duplicates.

How do I insert elements into a multimap?

You can insert elements into a multimap using the insert method, just like with a map, but you can insert multiple values for the same key.