运行 ID: 6440

Main.cc: In function ‘int main()’:
Main.cc:7:8: error: no match for ‘operator<<’ (operand types are ‘std::istream {aka std::basic_istream}’ and ‘int’)
     cin<
Main.cc:7:8: note:   no known conversion for argument 1 from ‘std::istream {aka std::basic_istream}’ to ‘int’
In file included from /usr/include/c++/7/string:52:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from Main.cc:1:
/usr/include/c++/7/bits/basic_string.h:6284:5: note: candidate: template 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++/7/bits/basic_string.h:6284:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’
     cin< 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++/7/system_error:217:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’
     cin< std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, _CharT)
     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:497:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’
     cin< std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, char)
     operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:502:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’
     cin< std::basic_ostream& std::operator<<(std::basic_ostream&, char)
     operator<<(basic_ostream& __out, char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:508:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin< std::basic_ostream& std::operator<<(std::basic_ostream&, signed char)
     operator<<(basic_ostream& __out, signed char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:514:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin< std::basic_ostream& std::operator<<(std::basic_ostream&, unsigned char)
     operator<<(basic_ostream& __out, unsigned char __c)
     ^~~~~~~~
/usr/include/c++/7/ostream:519:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin< std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const _CharT*)
     operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:539:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’
     cin< std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const char*)
     operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s)
     ^~~~~~~~
/usr/include/c++/7/bits/ostream.tcc:321:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream<_CharT, _Traits>’
     cin< std::basic_ostream& std::operator<<(std::basic_ostream&, const char*)
     operator<<(basic_ostream& __out, const char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:556:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin< std::basic_ostream& std::operator<<(std::basic_ostream&, const signed char*)
     operator<<(basic_ostream& __out, const signed char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:569:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin< std::basic_ostream& std::operator<<(std::basic_ostream&, const unsigned char*)
     operator<<(basic_ostream& __out, const unsigned char* __s)
     ^~~~~~~~
/usr/include/c++/7/ostream:574:5: note:   template argument deduction/substitution failed:
Main.cc:7:10: note:   ‘std::istream {aka std::basic_istream}’ is not derived from ‘std::basic_ostream’
     cin< typename std::enable_if >, std::__is_convertible_to_basic_ostream<_Ostream>, std::__is_insertable::__ostream_type, const _Tp&, void> >::value, typename std::__is_convertible_to_basic_ostream<_Tp>::__ostream_type>::type std::operator<<(_Ostream&&, const _Tp&)
     operator<<(_Ostream&& __os, const _Tp& __x)
     ^~~~~~~~
/usr/include/c++/7/ostream:682:5: note:   template argument deduction/substitution failed:
/usr/include/c++/7/ostream: In substitution of ‘template typename std::enable_if >, std::__is_convertible_to_basic_ostream<_Ostream>, std::__is_insertable::__ostream_type, const _Tp&, void> >::value, typename std::__is_convertible_to_basic_ostream<_Tp>::__ostream_type>::type std::operator<<(_Ostream&&, const _Tp&) [with _Ostream = std::basic_istream&; _Tp = int]’:
Main.cc:7:10:   required from here
/usr/include/c++/7/ostream:682:5: error: no type named ‘type’ in ‘struct std::enable_if’
Main.cc:9:21: error: expected ‘}’ at end of input
     cout<