Karte von Vektoren - wie es

Question

Ich habe einen folgenden Code tun:

std::map<std::wstring, std::vector<Table> > my_map; 
my_map[L"abc"].push_back(Table()); 

aber versuchen, es zu kompilieren es eine Menge Fehler {MSVC 2010} gibt, die ich nicht verstehe überhaupt nicht.

Also, eine rhetorische Frage: Warum MS gibt eine Reihe von Fehlern, die Menschen nicht verstehen können? Und zweitens: Wie repariere ich die zweite Zeile?

Vielen Dank.

Hier sind die Fehler für das Bezug:

2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::vector<_Ty,_Ax> &,const std::vector<_Ty,_Ax> &)' : could not deduce template argument for 'const std::vector<_Ty,_Ax> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\vector(1502) : see declaration of 'std::operator <' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(124) : while compiling class template member function 'bool std::less<_Ty>::operator()(const _Ty &,const _Ty &) const' 
2>   with 
2>   [ 
2>    _Ty=std::wstring 
2>   ] 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\map(71) : see reference to class template instantiation 'std::less<_Ty>' being compiled 
2>   with 
2>   [ 
2>    _Ty=std::wstring 
2>   ] 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xtree(451) : see reference to class template instantiation 'std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,_Mfl>' being compiled 
2>   with 
2>   [ 
2>    _Kty=std::wstring, 
2>    _Ty=std::vector<Table>, 
2>    _Pr=std::less<std::wstring>, 
2>    _Alloc=std::allocator<std::pair<const std::wstring,std::vector<Table>>>, 
2>    _Mfl=false 
2>   ] 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xtree(520) : see reference to class template instantiation 'std::_Tree_nod<_Traits>' being compiled 
2>   with 
2>   [ 
2>    _Traits=std::_Tmap_traits<std::wstring,std::vector<Table>,std::less<std::wstring>,std::allocator<std::pair<const std::wstring,std::vector<Table>>>,false> 
2>   ] 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xtree(659) : see reference to class template instantiation 'std::_Tree_val<_Traits>' being compiled 
2>   with 
2>   [ 
2>    _Traits=std::_Tmap_traits<std::wstring,std::vector<Table>,std::less<std::wstring>,std::allocator<std::pair<const std::wstring,std::vector<Table>>>,false> 
2>   ] 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\map(81) : see reference to class template instantiation 'std::_Tree<_Traits>' being compiled 
2>   with 
2>   [ 
2>    _Traits=std::_Tmap_traits<std::wstring,std::vector<Table>,std::less<std::wstring>,std::allocator<std::pair<const std::wstring,std::vector<Table>>>,false> 
2>   ] 
2>   C:\Users\Igor\OneDrive\Documents\dbhandler_app\dbinterface\database.h(115) : see reference to class template instantiation 'std::map<_Kty,_Ty>' being compiled 
2>   with 
2>   [ 
2>    _Kty=std::wstring, 
2>    _Ty=std::vector<Table> 
2>   ] 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::vector<_Ty,_Ax> &,const std::vector<_Ty,_Ax> &)' : could not deduce template argument for 'const std::vector<_Ty,_Ax> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\vector(1502) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::vector<_Ty,_Ax> &,const std::vector<_Ty,_Ax> &)' : could not deduce template argument for 'const std::vector<_Ty,_Ax> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\vector(1502) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::_Tree<_Traits> &,const std::_Tree<_Traits> &)' : could not deduce template argument for 'const std::_Tree<_Traits> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xtree(1885) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::_Tree<_Traits> &,const std::_Tree<_Traits> &)' : could not deduce template argument for 'const std::_Tree<_Traits> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xtree(1885) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::_Tree<_Traits> &,const std::_Tree<_Traits> &)' : could not deduce template argument for 'const std::_Tree<_Traits> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xtree(1885) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::unique_ptr<_Ty,_Dx> &,const std::unique_ptr<_Ty2,_Dx2> &)' : could not deduce template argument for 'const std::unique_ptr<_Ty,_Dx> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\memory(2582) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::unique_ptr<_Ty,_Dx> &,const std::unique_ptr<_Ty2,_Dx2> &)' : could not deduce template argument for 'const std::unique_ptr<_Ty,_Dx> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\memory(2582) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::unique_ptr<_Ty,_Dx> &,const std::unique_ptr<_Ty2,_Dx2> &)' : could not deduce template argument for 'const std::unique_ptr<_Ty,_Dx> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\memory(2582) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::reverse_iterator<_RanIt> &,const std::reverse_iterator<_RanIt2> &)' : could not deduce template argument for 'const std::reverse_iterator<_RanIt> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(1356) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::reverse_iterator<_RanIt> &,const std::reverse_iterator<_RanIt2> &)' : could not deduce template argument for 'const std::reverse_iterator<_RanIt> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(1356) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::reverse_iterator<_RanIt> &,const std::reverse_iterator<_RanIt2> &)' : could not deduce template argument for 'const std::reverse_iterator<_RanIt> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(1356) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::_Revranit<_RanIt,_Base> &,const std::_Revranit<_RanIt2,_Base2> &)' : could not deduce template argument for 'const std::_Revranit<_RanIt,_Base> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(1179) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::_Revranit<_RanIt,_Base> &,const std::_Revranit<_RanIt2,_Base2> &)' : could not deduce template argument for 'const std::_Revranit<_RanIt,_Base> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(1179) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::_Revranit<_RanIt,_Base> &,const std::_Revranit<_RanIt2,_Base2> &)' : could not deduce template argument for 'const std::_Revranit<_RanIt,_Base> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(1179) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::pair<_Ty1,_Ty2> &,const std::pair<_Ty1,_Ty2> &)' : could not deduce template argument for 'const std::pair<_Ty1,_Ty2> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\utility(318) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::pair<_Ty1,_Ty2> &,const std::pair<_Ty1,_Ty2> &)' : could not deduce template argument for 'const std::pair<_Ty1,_Ty2> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\utility(318) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2784: 'bool std::operator <(const std::pair<_Ty1,_Ty2> &,const std::pair<_Ty1,_Ty2> &)' : could not deduce template argument for 'const std::pair<_Ty1,_Ty2> &' from 'const std::wstring' 
2>   c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\utility(318) : see declaration of 'std::operator <' 
2>c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xfunctional(125): error C2676: binary '<' : 'const std::wstring' does not define this operator or a conversion to a type acceptable to the predefined operator 

Answer 1

Kratzer Kinn Hm. Diese Fehlermeldung sieht verdächtig:

2> c: \ Program Files (x86) \ Microsoft Visual Studio 10.0 \ VC \ include \ xfunctional (125): Fehler C2676: binary '<': ‚const std: : ‚definiert nicht, diesen Operator oder eine Umwandlung in einen Typ akzeptablen dem vordefinierten Operator

schweren Gegenstand zieht und plops es auf den Tisch sehe ich in meinen ... Glaskugel wstring ... Der Hyperlink Using an std::string as a key for an std::map schwebt geheimnisvoll in den Nebel

Ah ja! Das war's. Sie haben #include <string> vergessen.

Das ist, was passiert, wenn Sie:

1. Sie eine MCVE

2. Vernachlässige nicht produzieren den Rat eines vorherigen Kommentator zu folgen, um „überprüfen, ob Sie #include <string> haben“