Trier un vecteur de chaînes en utilisant des modèles

Question

Voici le code pour le tri d'une vector de string s

#include<iostream> 
    #include <vector> 
    #include <functional> 
    #include <algorithm> 
    #include <ostream> 
    using namespace std; 
    //using std::greater; 
    int main(){ 

     vector<string>s; 
     s.push_back("cat"); 
     s.push_back("antelope"); 
     s.push_back("dog"); 
     s.push_back("elephant"); 
     s.push_back("snake"); 
     sort(s.begin(),s.end(),greater<string>()); 
     for (auto i=s.begin();i!=s.end();++i){ 
      std::cout<<*i; 
     } 
      return 0; 
    } 

et voici les erreurs

1>------ Build started: Project: sort_string, Configuration: Debug Win32 ------ 
1>Build started 8/8/2010 4:40:45 PM. 
1>InitializeBuildStatus: 
1> Touching "Debug\sort_string.unsuccessfulbuild". 
1>ClCompile: 
1> sort_string.cpp 
1>c:\users\david\documents\visual studio 2010\projects\sort_string\sort_string\sort_string.cpp(18): error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'std::basic_string<_Elem,_Traits,_Ax>' (or there is no acceptable conversion) 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char>, 
1>    _Ax=std::allocator<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(679): could be 'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const char *)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(726): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,char)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(764): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const char *)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(811): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,char)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(937): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const signed char *)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(944): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,signed char)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(951): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const unsigned char *)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(958): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,unsigned char)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(968): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>,std::basic_string<_Elem,_Traits,_Ax>>(std::basic_ostream<_Elem,_Traits> &&,_Ty)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char>, 
1>    _Ax=std::allocator<char>, 
1>    _Ty=std::basic_string<char,std::char_traits<char>,std::allocator<char>> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(1085): or  'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const std::error_code &)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(186): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ostream<_Elem,_Traits> &(__cdecl *)(std::basic_ostream<_Elem,_Traits> &))' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(192): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_ios<_Elem,_Traits> &(__cdecl *)(std::basic_ios<_Elem,_Traits> &))' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(199): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::ios_base &(__cdecl *)(std::ios_base &))' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(206): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::_Bool)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(226): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(short)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(260): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned short)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(280): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(int)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(305): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned int)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(325): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(345): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned long)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(366): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(__int64)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(386): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(unsigned __int64)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(407): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(float)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(427): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(double)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(447): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(long double)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(467): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(const void *)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ostream(487): or  'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Traits>::operator <<(std::basic_streambuf<_Elem,_Traits> *)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   while trying to match the argument list '(std::ostream, std::basic_string<_Elem,_Traits,_Ax>)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char>, 
1>    _Ax=std::allocator<char> 
1>   ] 
1> 
1>Build FAILED. 
1> 
1>Time Elapsed 00:00:02.21 
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== 

Quelle est la cause de ces erreurs?

Answer 1

Il vous manque juste #include <string>.

Les erreurs ne se rapportent pas au tri, elles se rapportent à ne pas trouver une surcharge appropriée de << pour sortir une chaîne. Si vous utilisez std::string, incluez l'en-tête correspondant.

Answer 2

Vous n'avez pas #include <string>.

Answer 3

Utilisez #include<string>

Ce comportement est étrange dans Visual Studio qui ne fait pas l'erreur de compilation lorsque u utiliser chaîne directement sans spécifier #include<string> mais une erreur est générée lors de l'utilisation u chaîne avec un autre tout objet stl/fonction qui essaie d'utiliser l'un des opérateurs surchargés.