Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:20:8: error: no match for ‘operator<<’ (operand types are ‘std::ifstream {aka std::basic_ifstream<char>}’ and ‘double’) fout<<s/t; ^ In file included from /usr/include/c++/5/string:52:0, from /usr/include/c++/5/bits/locale_classes.h:40, from /usr/include/c++/5/bits/ios_base.h:41, from /usr/include/c++/5/ios:42, from /usr/include/c++/5/ostream:38, from /usr/include/c++/5/iostream:39, from user.cpp:1: /usr/include/c++/5/bits/basic_string.h:5172:5: note: candidate: template<class _CharT, class _Traits, class _Alloc> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&) operator<<(basic_ostream<_CharT, _Traits>& __os, ^ /usr/include/c++/5/bits/basic_string.h:5172:5: note: template argument deduction/substitution failed: user.cpp:20:12: note: ‘std::ifstream {aka std::basic_ifstream<char>}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’ fout<<s/t; ^ In file included from /usr/include/c++/5/bits/ios_base.h:46:0, from /usr/include/c++/5/ios:42, from /usr/include/c++/5/ostream:38, from /usr/include/c++/5/iostream:39, from user.cpp:1: /usr/include/c++/5/system_error:209:5: note: candidate: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::error_code&) operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e) ^ /usr/include/c++/5/system_error:209:5: note: template argument deduction/substitution failed: user.cpp:20:12: note: ‘std::ifstream {aka std::basic_ifstream<char>}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’ fout<<s/t; ^ In file included from /usr/include/c++/5/iostream:39:0, from user.cpp:1: /usr/include/c++/5/ostream:497:5: note: candidate: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, _CharT) operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) ^ /usr/include/c++/5/ostream:497:5: note: template argument deduction/substitution failed: user.cpp:20:12: note: ‘std::ifstream {aka std::basic_ifstream<char>}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’ fout<<s/t; ^ In file included from /usr/include/c++/5/iostream:39:0, from user.cpp:1: /usr/include/c++/5/ostream:502:5: note: candidate: template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, char) operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) ^ /usr/include/c++/5/ostream:502:5: note: template argument deduction/substitution failed: user.cpp:20:12: note: ‘std::ifstream {aka std::basic_ifstream<char>}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’ fout<<s/t; ^ In file included from /usr/include/c++/5/iostream:39:0, from user.cpp:1: