need STL set in insertion order

Question

How to store elements in set in insertion order. for example.

setmyset;

myset.insert(\"stack\");
myset.insert(\"overflow\");

Answer 1

I'm just wondering why nobody has suggested using such a nice library as Boost MultiIndex. Here's an example how to do that:

#include 
#include 
#include 
#include 
#include 

#include 

template
using my_set = boost::multi_index_container<
    T,
    boost::multi_index::indexed_by<
        boost::multi_index::sequenced<>,
        boost::multi_index::ordered_unique>
    >
>;

int main() {
    my_set set;
    set.push_back(10);
    set.push_back(20);
    set.push_back(3);
    set.push_back(11);
    set.push_back(1);
    
    // Prints elements of the set in order of insertion.
    const auto &index = set.get<0>();
    for (const auto &item : index) {
        std::cout << item << " ";
    }

    // Prints elements of the set in order of value.
    std::cout << "\n";
    const auto &ordered_index = set.get<1>();
    for (const auto &item : ordered_index) {
        std::cout << item << " ";
    }
}