C++11: std::map Iterators vs Vectors

What are the main differences between std::map iterators and vectors in C++11?

The main differences include how they store data, access patterns, and performance characteristics. std::map is an associative container that stores key-value pairs, while vectors are sequential containers that store elements in a contiguous memory block.

Can you explain how to iterate over a std::map using iterators?

Sure! You can use a for loop with the begin() and end() methods of the std::map. Here's an example:

std::map<int, std::string> myMap = {{1, "one"}, {2, "two"}};
for (auto it = myMap.begin(); it != myMap.end(); ++it) {
    std::cout << it->first << ": " << it->second << std::endl;
}

How does the performance of std::map compare to std::vector?

std::map has logarithmic time complexity for insertions and lookups due to its tree structure, while std::vector offers constant time complexity for access but linear time for insertions and deletions (except at the end). This makes vectors faster for indexed access.

When should I use std::map instead of std::vector?

Use std::map when you need to associate keys with values and require fast lookups based on those keys. If you only need to store a list of items and access them by index, std::vector is more efficient.