Borderou de evaluare (job #609938)

Eroare de compilare: main.cpp: In function 'int main()': main.cpp:6:6: error: no match for 'operator<<' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'int') 6 | cin << a; | ~~~ ^~ ~ | | | | | int | std::istream {aka std::basic_istream<char>} main.cpp:6:6: note: candidate: 'operator<<(int, int)' (built-in) 6 | cin << a; | ~~~~^~~~ main.cpp:6:6: note: no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'int' In file included from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/regex:62, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/i686-pc-linux-gnu/bits/stdc++.h:110, from main.cpp:1: /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/bits/regex.h:1647:5: note: candidate: 'template<class _Ch_type, class _Ch_traits, class _Bi_iter> std::basic_ostream<_CharT, _Traits>& std::__cxx11::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::__cxx11::sub_match<_Bi_iter>&)' 1647 | operator<<(basic_ostream<_Ch_type, _Ch_traits>& __os, | ^~~~~~~~ /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/bits/regex.h:1647:5: note: template argument deduction/substitution failed: main.cpp:6:9: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 6 | cin << a; | ^ In file included from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/string:55, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/bits/locale_classes.h:40, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/bits/ios_base.h:41, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/ios:42, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/istream:38, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/sstream:38, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/complex:45, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/ccomplex:39, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/i686-pc-linux-gnu/bits/stdc++.h:54, from main.cpp:1: /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/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/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/bits/basic_string.h:6468:5: note: template argument deduction/substitution failed: main.cpp:6:9: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>' 6 | cin << a; | ^ In file included from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/bits/ios_base.h:46, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/ios:42, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/istream:38, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/sstream:38, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/complex:45, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/ccomplex:39, from /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/i686-pc-linux-gnu/bits/stdc++.h:54, from main.cpp:1: /usr/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/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/lib/gcc/i686-pc-linux-gnu/10.3.0/include/g++-v10/system_error:262:5: note: template argument deduction/substitution failed: