example2_custom_comparator.cpp

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#include <iostream>
#include <set>
#include <string>

struct Person {
    std::string name;
    int age;

    bool operator<(const Person& other) const {
        return age < other.age;
    }
};

// Custom comparator for descending order
struct PersonComparator {
    bool operator()(const Person& a, const Person& b) const {
        return a.age > b.age;
    }
};

int main() {
    std::set<Person, PersonComparator> people;

    people.insert({"Alice", 30});
    people.insert({"Bob", 25});
    people.insert({"Charlie", 35});
    people.insert({"David", 28});

    for (const auto& person : people) {
        std::cout << person.name << ": " << person.age << std::endl;
    }

    return 0;
}