How do I insert elements into a std::map in C++17?

How do I insert elements into a std::map in C++17?

In C++17, you can insert elements into a std::map using the insert() function or the emplace() function. For example:

#include <map>
#include <string>

int main() {
    std::map<int, std::string> myMap;
    myMap.insert({1, "one"}); // Using insert
    myMap.emplace(2, "two"); // Using emplace
    return 0;
}

What's the difference between insert and emplace?

The main difference is that insert creates a pair and then inserts it, while emplace constructs the pair in place, which can be more efficient.

Can I use the subscript operator to insert elements?

Yes, you can use the subscript operator to insert or update elements in a std::map. For example:

myMap[3] = "three"; // Inserts or updates the value for key 3

What happens if I insert a duplicate key?

If you insert a duplicate key, the existing value for that key will be replaced with the new value.