When to use unordered_map vs vector in C++?

Can you explain when to use unordered_map instead of vector in C++?

Sure! Use unordered_map when you need fast lookups by key, while vector is better for ordered data and sequential access.

What are the performance differences between them?

Unordered_map offers average O(1) time complexity for lookups, while vector has O(n) for searching unless sorted.

Are there any scenarios where vector is preferred over unordered_map?

Yes, if you need to maintain order or perform frequent insertions/deletions at the end, vector is more efficient.

Can you give an example of each in code?

Certainly! For unordered_map: std::unordered_map<int, std::string> myMap; and for vector: std::vector<int> myVector;.