unordered in a ordered map - C++

Question

So I have a web scraper that would scrape tons of article off of a news website. Currently, I am writing a function to filter out the article by months. (Code is shown below) I have stored the months and number of post on a map. However, when I printed out the map, the key and value are not order?

CODE

#include "Source.cpp"
#include <map>

int main() {

    std::map<std::string, int> numberOfPost;
    int janCounter = 0;
    int febCounter = 0;
    int marCounter = 0;
    int aprCounter = 0;
    int mayCounter = 0;
    int juneCounter = 0;
    int julyCounter = 0;
    int augCounter = 0;
    int septCounter = 0;
    int octCounter = 0;
    int novCounter = 0;
    int decCounter = 0;

    //Calling STScraper and load into Vector
    std::vector<STPost>stposts = STScraper();
    for (auto i = stposts.begin(); i != stposts.end(); ++i) {
        std::tm dt = (*i).getTime();
        //std::wcout << dt.tm_mon << std::endl;
        if (dt.tm_mon == 0)
        {
            janCounter++;
        }
        else if (dt.tm_mon == 1)
        {
            febCounter++;
        }
        else if (dt.tm_mon == 2)
        {
            marCounter++;
        }
        else if (dt.tm_mon == 3)
        {
            aprCounter++;
        }
        else if (dt.tm_mon == 4)
        {
            mayCounter++;
        }
        else if (dt.tm_mon == 5)
        {
            juneCounter++;
        }
        else if (dt.tm_mon == 6)
        {
            julyCounter++;
        }
        else if (dt.tm_mon == 7)
        {
            augCounter++;
        }
        else if (dt.tm_mon == 8)
        {
            septCounter++;
        }
        else if (dt.tm_mon == 9)
        {
            octCounter++;
        }
        else if (dt.tm_mon == 10)
        {
            novCounter++;
        }
        else if (dt.tm_mon == 11)
        {
            decCounter++;
        }
    }
    numberOfPost.insert(std::pair<std::string, int>("January", janCounter));
    numberOfPost.insert(std::pair<std::string, int>("Feburary", febCounter));
    numberOfPost.insert(std::pair<std::string, int>("March", marCounter));
    numberOfPost.insert(std::pair<std::string, int>("April", aprCounter));
    numberOfPost.insert(std::pair<std::string, int>("May", mayCounter));
    numberOfPost.insert(std::pair<std::string, int>("June", juneCounter));
    numberOfPost.insert(std::pair<std::string, int>("July", julyCounter));
    numberOfPost.insert(std::pair<std::string, int>("August", augCounter));
    numberOfPost.insert(std::pair<std::string, int>("September", septCounter));
    numberOfPost.insert(std::pair<std::string, int>("October", octCounter));
    numberOfPost.insert(std::pair<std::string, int>("November", novCounter));
    numberOfPost.insert(std::pair<std::string, int>("December", decCounter));

    std::map<std::string, int>::iterator itr;
    std::cout << "\tKEY\tELEMENT\n";
    for (auto& p : numberOfPost) {
        std::cout << '\t' << p.first
             << '\t' << p.second << '\n';
    }
    std::cout << std::endl;

    return 0;
}

As you can see from my code, I create a loop to count the number of post by months and stored it in a map. However, when I printed out the map, the output does not show the order from Jan to dec. So how do I edit my code such that when I print my map out it would show from Jan to dec ?

OUTPUT

Answer 1

Using a custom sort for your map, you can do something like this:

struct customSort {
    bool operator()( const std::string &a, const std::string &b ) const {
        static const std::unordered_map<std::string, int> months = {
            { "January", 1 },
            { "Feburary", 2 },
            { "March", 3 },
            { "April", 4 },
            { "May", 5 },
            { "June", 6 },
            { "July", 7 },
            { "August", 8 },
            { "September", 9 },
            { "October", 10 },
            { "November", 11 },
            { "December", 12 },
        };

        return months.at( a ) < months.at( b );
    }
};
std::map<std::string, int, customSort> numberOfPost;

This will sort the your map by the month. It will also throw an exception if you try to put in something that isn't a valid month.