如何实现boost multi_index

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

using namespace boost::multi_index;

struct employee {
  std::string name;
  int age;
  double salary;
};

typedef multi_index_container<
  employee,
  indexed_by<
    ordered_unique<member<employee, std::string, &employee::name>>,
    ordered_non_unique<member<employee, int, &employee::age>>,
    ordered_non_unique<member<employee, double, &employee::salary>>
  >
> employee_set;

int main() {
  employee_set es;

  es.insert({"John", 25, 5000.0});
  es.insert({"Jane", 30, 6000.0});
  es.insert({"Bob", 27, 5500.0});

  // 按名字查询
  auto name_view = es.get<0>();
  auto it = name_view.find("John");
  std::cout << "Name: " << it->name << ", Age: " << it->age << ", Salary: " << it->salary<< std::endl;

  // 按年龄查询
  auto age_view = es.get<1>();
  auto range = age_view.equal_range(27);
  for (auto it = range.first; it != range.second; ++it) {
    std::cout << "Name: " << it->name << ", Age: " << it->age << ", Salary: " << it->salary<< std::endl;
  }

  // 按薪水查询
  auto salary_view = es.get<2>();
  auto salary_range = salary_view.range(5000.0, 6000.0);
  for (auto it = salary_range.first; it != salary_range.second; ++it) {
    std::cout << "Name: " << it->name << ", Age: " << it->age << ", Salary: " << it->salary<< std::endl;
  }

  return 0;
}