multi_index_container

Posted 2020-12-25 lehoho

转自：https://blog.csdn.net/buptman1/article/details/38657807

multi_index_container：

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。

 

#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;
}

#include "boost/multi_index_container.hpp"
#include "boost/multi_index/member.hpp"
#include "boost/multi_index/ordered_index.hpp"

using boost::multi_index_container;
using namespace boost::multi_index;

struct stu_num{};	// 索引-学号
struct stu_name{};  // 索引-姓名
struct stu_age{};	// 索引-年龄

typedef
boost::multi_index_container<
	Student,
	indexed_by<
		ordered_unique<
                  // 学号是唯一值的索引
		tag<stu_num>,  BOOST_MULTI_INDEX_MEMBER(Student,unsigned int,stu_num)>,
    		// 姓名是非唯一值的索引
                     ordered_non_unique<
		tag<stu_name>,BOOST_MULTI_INDEX_MEMBER(Student,std::string,stu_name)>,
                  // 年龄是非唯一值的索引
		ordered_non_unique<
		tag<stu_age>, BOOST_MULTI_INDEX_MEMBER(Student,unsigned int,stu_age)>	
	>
> StudentContainer;

	// 用名字作为索引
	StudentContainer::index<stu_name>::type& indexOfName = studentsets.get<stu_name>();

	// 查找名叫李四的人
	StudentContainer::index<stu_name>::type::iterator it = indexOfName.find("李四");

	// 找到了？
	if( it != indexOfName.end() )
	{
               // it就是一个Student序列的迭代器，现在你可以
                 // 像普通迭代器一样操作它了，比如cout << *it
	}

	// 用名字作为索引
	StudentContainer::index<stu_name>::type& indexOfName = studentsets.get<stu_name>();


	// 查找名叫张三的人的下界
	StudentContainer::index<stu_name>::type::iterator itL = indexOfName.lower_bound("张三");

	// 查找名叫张三的人的上界
	StudentContainer::index<stu_name>::type::iterator itU = indexOfName.upper_bound("张三");

         // 遍历输出所有名叫“张三”的学生信息
	while(itL != itU)
	{
		std::cout << *itL;
		++itL;
	}

 

 

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