Question

我可以通过从modify获得的迭代器在boost::multi_index_container上调用get<0>().find()。但是，当我尝试在get<1>().find()上执行相同操作时，我收到编译错误。

是否可以通过第二个索引上的迭代器进行修改？

我正在使用g++4.9.2和boost 1.55。

代码是

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

using std::string;
using boost::multi_index::indexed_by;
using boost::multi_index::ordered_non_unique;
using boost::multi_index::member;

struct Person
{
    string FamilyName;
    string PersonalName;
    //        string MiddleName;
};

typedef boost::multi_index_container
<
    Person,
    indexed_by<
        ordered_non_unique<member<Person, string, &Person::FamilyName>>,
        ordered_non_unique<member<Person, string, &Person::PersonalName>>
    >
>
PersonList;

main()
{
    PersonList people;

    {
        string toFind = "Jones";
        string toReplace = "Smith";

        PersonList::nth_index<0>::type::const_iterator itr0( people.get<0>().find(toFind) );
        const PersonList::nth_index<0>::type::const_iterator end0(people.get<0>().cend());

        for( ; itr0!= end0; itr0++)
        {
            people.modify(itr0, [&](Person &e){ e.FamilyName = toReplace; });
        }

    }

    {
        string toFind = "Fred";
        string toReplace = "Barney";

        PersonList::nth_index<1>::type::const_iterator itr1( people.get<1>().find(toFind) );
        const PersonList::nth_index<1>::type::const_iterator end1(people.get<1>().cend());

        for( ; itr1!= end1; itr1++)
        {
            people.modify(itr1, [&](Person &e){ e.PersonalName = toReplace; });
        }
    }    
}

，错误是

LANG=C g++ -std=c++11 boost-test.cpp

boost-test.cpp: In function 'int main()':

boost-test.cpp:57:82: error: no matching function for call to 'boost::multi_index::multi_index_container<Person, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName> >, boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName> > > >::modify(boost::multi_index::detail::ordered_index<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName>, std::less<std::basic_string<char> >, boost::multi_index::detail::nth_layer<2, Person, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName> >, boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName> > >, std::allocator<Person> >, boost::mpl::vector0<mpl_::na>, boost::multi_index::detail::ordered_non_unique_tag>::const_iterator&, main()::<lambda(Person&)>)'

                 people.modify(itr1, [&](Person &e){ e.PersonalName = toReplace; });

boost-test.cpp:57:82: note: candidates are:

In file included from boost-test.cpp:4:0:

/usr/include/boost/multi_index/ordered_index.hpp:413:8: note: template<class Modifier> bool boost::multi_index::detail::ordered_index<KeyFromValue, Compare, SuperMeta, TagList, Category>::modify(boost::multi_index::detail::ordered_index<KeyFromValue, Compare, SuperMeta, TagList, Category>::iterator, Modifier) [with Modifier = Modifier; KeyFromValue = boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName>; Compare = std::less<std::basic_string<char> >; SuperMeta = boost::multi_index::detail::nth_layer<1, Person, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName> >, boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName> > >, std::allocator<Person> >; TagList = boost::mpl::vector0<mpl_::na>; Category = boost::multi_index::detail::ordered_non_unique_tag]

   bool modify(iterator position,Modifier mod)

        ^

/usr/include/boost/multi_index/ordered_index.hpp:413:8: note:   template argument deduction/substitution failed:

boost-test.cpp:57:82: note:   cannot convert 'itr1' (type 'boost::multi_index::detail::ordered_index<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName>, std::less<std::basic_string<char> >, boost::multi_index::detail::nth_layer<2, Person, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName> >, boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName> > >, std::allocator<Person> >, boost::mpl::vector0<mpl_::na>, boost::multi_index::detail::ordered_non_unique_tag>::const_iterator {aka boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Person, std::allocator<Person> > > >}') to type 'boost::multi_index::detail::ordered_index<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName>, std::less<std::basic_string<char> >, boost::multi_index::detail::nth_layer<1, Person, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName> >, boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName> > >, std::allocator<Person> >, boost::mpl::vector0<mpl_::na>, boost::multi_index::detail::ordered_non_unique_tag>::iterator {aka boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Person, std::allocator<Person> > > > >}'

                 people.modify(itr1, [&](Person &e){ e.PersonalName = toReplace; });

                                                                                  ^

In file included from boost-test.cpp:4:0:

/usr/include/boost/multi_index/ordered_index.hpp:434:8: note: template<class Modifier, class Rollback> bool boost::multi_index::detail::ordered_index<KeyFromValue, Compare, SuperMeta, TagList, Category>::modify(boost::multi_index::detail::ordered_index<KeyFromValue, Compare, SuperMeta, TagList, Category>::iterator, Modifier, Rollback) [with Modifier = Modifier; Rollback = Rollback; KeyFromValue = boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName>; Compare = std::less<std::basic_string<char> >; SuperMeta = boost::multi_index::detail::nth_layer<1, Person, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName> >, boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName> > >, std::allocator<Person> >; TagList = boost::mpl::vector0<mpl_::na>; Category = boost::multi_index::detail::ordered_non_unique_tag]

   bool modify(iterator position,Modifier mod,Rollback back)

        ^

/usr/include/boost/multi_index/ordered_index.hpp:434:8: note:   template argument deduction/substitution failed:

boost-test.cpp:57:82: note:   cannot convert 'itr1' (type 'boost::multi_index::detail::ordered_index<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName>, std::less<std::basic_string<char> >, boost::multi_index::detail::nth_layer<2, Person, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName> >, boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName> > >, std::allocator<Person> >, boost::mpl::vector0<mpl_::na>, boost::multi_index::detail::ordered_non_unique_tag>::const_iterator {aka boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Person, std::allocator<Person> > > >}') to type 'boost::multi_index::detail::ordered_index<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName>, std::less<std::basic_string<char> >, boost::multi_index::detail::nth_layer<1, Person, boost::multi_index::indexed_by<boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::FamilyName> >, boost::multi_index::ordered_non_unique<boost::multi_index::member<Person, std::basic_string<char>, &Person::PersonalName> > >, std::allocator<Person> >, boost::mpl::vector0<mpl_::na>, boost::multi_index::detail::ordered_non_unique_tag>::iterator {aka boost::multi_index::detail::bidir_node_iterator<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::ordered_index_node<boost::multi_index::detail::index_node_base<Person, std::allocator<Person> > > > >}'

                 people.modify(itr1, [&](Person &e){ e.PersonalName = toReplace; });

                                                                                  ^

Answer 1

替换

people.modify(itr1, [&](Person &e){ e.PersonalName = toReplace; });

与

people.get<1>().modify(itr1, [&](Person &e){ e.PersonalName = toReplace; });

C ++ boost multi_index_container修改get_nth＆lt; 1＆gt;

1 个答案: