Eroare de compilare: main.cpp: In function 'int main()': main.cpp:30:21: error: no match for 'operator<<' (operand types are 'std::ifstream' {aka 'std::basic_ifstream<char>'} and 'int') 30 | fin << a; | ~~~ ^~ ~ | | | | | int | std::ifstream {aka std::basic_ifstream<char>} main.cpp:30:21: note: candidate: 'operator<<(int, int)' (built-in) 30 | fin << a; | ~~~~^~~~ main.cpp:30:21: note: no known conversion for argument 1 from 'std::ifstream' {aka 'std::basic_ifstream<char>'} to 'int' In file included from /usr/include/c++/12.2.1/bits/basic_string.h:47, from /usr/include/c++/12.2.1/string:53, from /usr/include/c++/12.2.1/bits/locale_classes.h:40, from /usr/include/c++/12.2.1/bits/ios_base.h:41, from /usr/include/c++/12.2.1/ios:42, from /usr/include/c++/12.2.1/ostream:38, from /usr/include/c++/12.2.1/iostream:39, from main.cpp:1: /usr/include/c++/12.2.1/string_view:672:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, basic_string_view<_CharT, _Traits>)' 672 | operator<<(basic_ostream<_CharT, _Traits>& __os, | ^~~~~~~~ /usr/include/c++/12.2.1/string_view:672:5: note: template argument deduction/substitution failed: main.cpp:30:24: note: 'std::ifstream' {aka 'std::basic_ifstream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 30 | fin << a; | ^ /usr/include/c++/12.2.1/bits/basic_string.h:3883:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)' 3883 | operator<<(basic_ostream<_CharT, _Traits>& __os, | ^~~~~~~~ /usr/include/c++/12.2.1/bits/basic_string.h:3883:5: note: template argument deduction/substitution failed: main.cpp:30:24: note: 'std::ifstream' {aka 'std::basic_ifstream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 30 | fin << a; | ^ In file included from /usr/include/c++/12.2.1/bits/ios_base.h:46: /usr/include/c++/12.2.1/system_error:279:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const error_code&)' 279 | operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e) | ^~~~~~~~ /usr/include/c++/12.2.1/system_error:279:5: note: template argument deduction/substitution failed: main.cpp:30:24: note: 'std::ifstream' {aka 'std::basic_ifstream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 30 | fin << a; | ^ /usr/include/c++/12.2.1/ostream:507:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, _CharT)' 507 | operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) | ^~~~~~~~ /usr/include/c++/12.2.1/ostream:507:5: note: template argument deduction/substitution failed: main.cpp:30:24: note: 'std::ifstream' {aka 'std::basic_ifstream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 30 | fin << a; | ^ /usr/include/c++/12.2.1/ostream:517:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, char)' 517 | operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) Non zero exit status: 1