Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:9:12: error: no matching function for call to ‘std::basic_ifstream<char>::open()’ f.open(); ^ In file included from user.cpp:2:0: /usr/include/c++/6/fstream:595:7: note: candidate: void std::basic_ifstream<_CharT, _Traits>::open(const char*, std::ios_base::openmode) [with _CharT = char; _Traits = std::char_traits<char>; std::ios_base::openmode = std::_Ios_Openmode] open(const char* __s, ios_base::openmode __mode = ios_base::in) ^~~~ /usr/include/c++/6/fstream:595:7: note: candidate expects 2 arguments, 0 provided /usr/include/c++/6/fstream:615:7: note: candidate: void std::basic_ifstream<_CharT, _Traits>::open(const string&, std::ios_base::openmode) [with _CharT = char; _Traits = std::char_traits<char>; std::__cxx11::string = std::__cxx11::basic_string<char>; std::ios_base::openmode = std::_Ios_Openmode] open(const std::string& __s, ios_base::openmode __mode = ios_base::in) ^~~~ /usr/include/c++/6/fstream:615:7: note: candidate expects 2 arguments, 0 provided