How do I reserve capacity and shrink-to-fit with std::map?

In C++, the `std::map` container automatically manages its capacity, meaning it does not provide direct methods to reserve capacity as one might with `std::vector`. However, you can optimize performance by using the right techniques when inserting elements.

To achieve a similar effect to reserving capacity, consider using `insert` or `emplace` methods appropriately to minimize reallocations during element insertion.

As for shrinking a `std::map`, it is managed automatically as items are removed. If you wish to optimize memory usage, one of the best practices is to clear the map, which will free up the memory, or to recreate the map if it has been significantly reduced in size.


            // Example of using std::map in C++
            #include <map>
            #include <iostream>

            int main() {
                std::map myMap;
                
                // Inserting elements
                myMap.emplace(1, "One");
                myMap.emplace(2, "Two");
                myMap.emplace(3, "Three");

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

                // Clearing the map (shrinks the map)
                myMap.clear();
                return 0;
            }

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How do I reserve capacity and shrink-to-fit with std::map?

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How do I reserve capacity and shrink-to-fit with std::map?

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