C++ Map vs Unordered Map: What's the Difference?

What are the main differences between map and unordered_map in C++?

The main differences are that map is ordered and uses a binary tree, while unordered_map is unordered and uses a hash table.

Which one is faster for lookups?

unordered_map is generally faster for lookups due to its average O(1) time complexity, compared to O(log n) for map.

Are there any situations where I should prefer map over unordered_map?

Yes, if you need to maintain the order of elements or require sorted keys, then map is the better choice.

Can you give an example of when to use unordered_map?

Use unordered_map when you need fast access and don't care about the order, like counting occurrences of items.