How do I iterate over a map in C++?

How do I iterate over a map in C++?

You can iterate over a map in C++ using a for loop. Here's an example:

#include <iostream>
#include <map>

int main() {
    std::map<int, std::string> myMap = {{1, "One"}, {2, "Two"}, {3, "Three"}};
    for (const auto& pair : myMap) {
        std::cout << pair.first << " : " << pair.second << std::endl;
    }
    return 0;
}

What if I want to modify the values while iterating?

If you want to modify the values, you can use a reference in the loop. Here's how:

for (auto& pair : myMap) {
    pair.second += " modified"; // Modifying the value
}

Can I use iterators instead of a range-based for loop?

Yes, you can use iterators. Here's an example:

for (auto it = myMap.begin(); it != myMap.end(); ++it) {
    std::cout << it->first << " : " << it->second << std::endl;
}

Are there any performance considerations when iterating over a map?

Yes, iterating over a map is generally O(n) in complexity, but keep in mind that maps are usually implemented as red-black trees, which can affect performance compared to other data structures like vectors.