如何通过多个键索引和查询STL映射容器？

#include<iostream>
#include<boost/multi_index_container.hpp>
#include<boost/multi_index/ordered_index.hpp>
#include<boost/multi_index/member.hpp>
#include<boost/multi_index/composite_key.hpp>
#include<string>
#include<tuple>

// 定义一个结构体，用于存储数据
struct Person {
    std::string name;
    int age;
    std::string city;

    // 构造函数
    Person(const std::string& name, int age, const std::string& city)
        : name(name), age(age), city(city) {}
};

// 定义一个映射容器，包含两个键索引
typedef boost::multi_index_container<
    Person,
    boost::multi_index::indexed_by<
        // 第一个键索引：按照年龄排序
        boost::multi_index::ordered_unique<
            boost::multi_index::member<Person, int, &Person::age>
        >,
        // 第二个键索引：按照城市和年龄排序
        boost::multi_index::ordered_unique<
            boost::multi_index::composite_key<
                Person,
                boost::multi_index::member<Person, std::string, &Person::city>,
                boost::multi_index::member<Person, int, &Person::age>
            >
        >
    >
> PersonContainer;

int main() {
    // 创建一个映射容器
    PersonContainer persons;

    // 向映射容器中添加数据
    persons.insert(Person("Tom", 25, "New York"));
    persons.insert(Person("Jerry", 30, "Los Angeles"));
    persons.insert(Person("Alice", 20, "New York"));
    persons.insert(Person("Bob", 25, "Los Angeles"));

    // 通过第一个键索引查询
    auto& age_index = persons.get<0>();
    auto age_range = age_index.equal_range(25);
    for (auto it = age_range.first; it != age_range.second; ++it) {
        std::cout << "Name: " << it->name << ", Age: " << it->age << ", City: " << it->city<< std::endl;
    }

    // 通过第二个键索引查询
    auto& city_age_index = persons.get<1>();
    auto city_age_range = city_age_index.equal_range(std::make_tuple("New York", 25));
    for (auto it = city_age_range.first; it != city_age_range.second; ++it) {
        std::cout << "Name: " << it->name << ", Age: " << it->age << ", City: " << it->city<< std::endl;
    }

    return 0;
}