Eroare de compilare: main.cpp: In function 'int main()': main.cpp:12:11: error: no match for 'operator<<' (operand types are 'std::ifstream' {aka 'std::basic_ifstream<char>'} and 'int') 12 | in<<x; | ~~^~~ | | | | | int | std::ifstream {aka std::basic_ifstream<char>} main.cpp:12:11: note: candidate: 'operator<<(int, int)' (built-in) 12 | in<<x; | ~~^~~ main.cpp:12:11: note: no known conversion for argument 1 from 'std::ifstream' {aka 'std::basic_ifstream<char>'} to 'int' In file included from /usr/include/c++/10/string:55, from /usr/include/c++/10/bits/locale_classes.h:40, from /usr/include/c++/10/bits/ios_base.h:41, from /usr/include/c++/10/ios:42, from /usr/include/c++/10/ostream:38, from /usr/include/c++/10/iostream:39, from main.cpp:1: /usr/include/c++/10/bits/basic_string.h:6468:5: 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>&)' 6468 | operator<<(basic_ostream<_CharT, _Traits>& __os, | ^~~~~~~~ /usr/include/c++/10/bits/basic_string.h:6468:5: note: template argument deduction/substitution failed: main.cpp:12:13: note: 'std::ifstream' {aka 'std::basic_ifstream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 12 | in<<x; | ^ In file included from /usr/include/c++/10/bits/ios_base.h:46, from /usr/include/c++/10/ios:42, from /usr/include/c++/10/ostream:38, from /usr/include/c++/10/iostream:39, from main.cpp:1: /usr/include/c++/10/system_error:262:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::error_code&)' 262 | operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e) | ^~~~~~~~ /usr/include/c++/10/system_error:262:5: note: template argument deduction/substitution failed: main.cpp:12:13: note: 'std::ifstream' {aka 'std::basic_ifstream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 12 | in<<x; | ^ In file included from /usr/include/c++/10/iostream:39, from main.cpp:1: /usr/include/c++/10/ostream:506:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, _CharT)' 506 | operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) | ^~~~~~~~ /usr/include/c++/10/ostream:506:5: note: template argument deduction/substitution failed: main.cpp:12:13: note: 'std::ifstream' {aka 'std::basic_ifstream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 12 | in<<x; | ^ In file included from /usr/include/c++/10/iostream:39, from main.cpp:1: /usr/include/c++/10/ostream:511:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, char)' 511 | operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) Non zero exit status: 1