cpp map iterate over keys
#include <iostream>
#include <map>
int main()
{
    std::map<std::string, int> myMap;
    myMap["one"] = 1;
    myMap["two"] = 2;
    myMap["three"] = 3;
    for ( const auto &myPair : myMap ) {
        std::cout << myPair.first << "n";
    }
}
