What are the differences between std::set and std::unordered_set in C++11?

Can you explain the differences between std::set and std::unordered_set in C++11?

Sure! The main difference is that std::set is ordered, while std::unordered_set is not. This affects how elements are stored and accessed.

What does it mean for std::set to be ordered?

An ordered set maintains the elements in a specific order, typically sorted based on the value of the elements. This allows for efficient range queries.

And how does that affect performance?

std::set has logarithmic time complexity for insertions, deletions, and lookups due to its underlying balanced tree structure. In contrast, std::unordered_set offers average constant time complexity for these operations, but it does not maintain any order.

Are there any scenarios where I should prefer one over the other?

Yes, if you need to maintain order or perform range queries, use std::set. If you prioritize performance and don't need order, std::unordered_set is the better choice.