How do I sort and stable_sort elements with std::map?

In C++, std::map is an associative container that stores elements in key-value pairs. Since it is inherently sorted by keys, you don't need to sort it explicitly. However, if you want to sort by values or maintain the order while performing stable operations, you might need to utilize additional structures.

Here's how you can do that by first copying the elements to a vector, sorting it, and then if needed, using std::stable_sort to maintain the relative order of elements with equivalent values.


        #include <iostream>
        #include <map>
        #include <vector>
        #include <algorithm>

        int main() {
            std::map myMap = {
                {1, "Apple"},
                {2, "Orange"},
                {3, "Banana"},
                {4, "Grape"},
                {5, "Banana"}
            };

            // Copy elements to a vector
            std::vector<:pair std::string>> vec(myMap.begin(), myMap.end());

            // Sort by values using stable_sort
            std::stable_sort(vec.begin(), vec.end(), [](const auto& a, const auto& b) {
                return a.second < b.second;
            });

            // Print sorted elements
            for (const auto& pair : vec) {
                std::cout << pair.first << ": " << pair.second << std::endl;
            }

            return 0;
        }

C++ std::map sort stable_sort associative container

How do I sort and stable_sort elements with std::map?

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How do I sort and stable_sort elements with std::map?

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