boost multi_index_container 基本介绍

Boost Multi-index Containers Library定义了multi_index_container模板类，可以从不同的维度建索引、排序和存取。

如上图，容器multi_index_container分别从shape,number和sequenced(默认插入的顺序)三个维度对元素进行管理。

使用如下：

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

using namespace boost;
using namespace boost::multi_index;
using namespace std;
struct Employee{
  int id;
  string name;
  int age;

  Employee(int id_,std::string name_,int age_):id(id_),name(name_),age(age_){}

  friend std::ostream& operator<<(std::ostream& os,const Employee& e)
  {
    os<<e.id<<" "<<e.name<<" "<<e.age<<std::endl;
    return os;
  }
};

typedef multi_index_container<
  Employee,
  indexed_by<
    ordered_unique<member<Employee, int, &Employee::id> >,
    ordered_non_unique<member<Employee, string, &Employee::name> >,
    ordered_non_unique<member<Employee, int, &Employee::age> >
  >
> EmployeeContainer;

typedef EmployeeContainer::nth_index<0>::type IdIndex;
typedef EmployeeContainer::nth_index<1>::type NameIndex;
typedef EmployeeContainer::nth_index<2>::type AgeIndex;

int main(){
  EmployeeContainer con;
  con.insert(Employee(0,"Joe",31));
  con.insert(Employee(1,"Robert",27));
  con.insert(Employee(2,"John",40));

  IdIndex& ids = con.get<0>();
  copy(ids.begin(),ids.end(), ostream_iterator<Employee>(cout));
  cout << endl;

  NameIndex& names = con.get<1>();
  copy(names.begin(), names.end(), ostream_iterator<Employee>(cout));
  cout << endl;

  names.erase(names.begin());

  AgeIndex& ages = con.get<2>();
  copy(ages.begin(), ages.end(), ostream_iterator<Employee>(cout));
  cout << endl;

  return 0;
}