foo.cc: In function 'int main()':
foo.cc:6:5: error: no match for 'operator<<' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'int')
6 | cin<<x;
| ~~~^~~
| | |
| | int
| std::istream {aka std::basic_istream<char>}
foo.cc:6:5: note: candidate: 'operator<<(int, int)' <built-in>
6 | cin<<x;
| ~~~^~~
foo.cc:6:5: note: no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'int'
In file included from /usr/include/c++/9/string:55,
from /usr/include/c++/9/bits/locale_classes.h:40,
from /usr/include/c++/9/bits/ios_base.h:41,
from /usr/include/c++/9/ios:42,
from /usr/include/c++/9/ostream:38,
from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/bits/basic_string.h:6419:5: 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>&)'
6419 | operator<<(basic_ostream<_CharT, _Traits>& __os,
| ^~~~~~~~
/usr/include/c++/9/bits/basic_string.h:6419:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/bits/ios_base.h:46,
from /usr/include/c++/9/ios:42,
from /usr/include/c++/9/ostream:38,
from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/system_error:217:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const std::error_code&)'
217 | operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
| ^~~~~~~~
/usr/include/c++/9/system_error:217:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/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++/9/ostream:506:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/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)
| ^~~~~~~~
/usr/include/c++/9/ostream:511:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/ostream:517:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, char)'
517 | operator<<(basic_ostream<char, _Traits>& __out, char __c)
| ^~~~~~~~
/usr/include/c++/9/ostream:517:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/ostream:523:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, signed char)'
523 | operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
| ^~~~~~~~
/usr/include/c++/9/ostream:523:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/ostream:528:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, unsigned char)'
528 | operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
| ^~~~~~~~
/usr/include/c++/9/ostream:528:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/ostream:548:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const _CharT*)'
548 | operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
| ^~~~~~~~
/usr/include/c++/9/ostream:548:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/ostream:702,
from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/bits/ostream.tcc:321:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const char*)'
321 | operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s)
| ^~~~~~~~
/usr/include/c++/9/bits/ostream.tcc:321:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/ostream:565:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const char*)'
565 | operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
| ^~~~~~~~
/usr/include/c++/9/ostream:565:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/ostream:578:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const signed char*)'
578 | operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
| ^~~~~~~~
/usr/include/c++/9/ostream:578:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/ostream:583:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const unsigned char*)'
583 | operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s)
| ^~~~~~~~
/usr/include/c++/9/ostream:583:5: note: template argument deduction/substitution failed:
foo.cc:6:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
6 | cin<<x;
| ^
In file included from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/ostream:691:5: note: candidate: 'template<class _Ostream, class _Tp> typename std::enable_if<std::__and_<std::__not_<std::is_lvalue_reference<_Tp> >, std::__is_convertible_to_basic_ostream<_Ostream>, std::__is_insertable<typename std::__is_convertible_to_basic_ostream<_Tp>::__ostream_type, const _Tp&, void> >::value, typename std::__is_convertible_to_basic_ostream<_Tp>::__ostream_type>::type std::operator<<(_Ostream&&, const _Tp&)'
691 | operator<<(_Ostream&& __os, const _Tp& __x)
| ^~~~~~~~
/usr/include/c++/9/ostream:691:5: note: template argument deduction/substitution failed:
/usr/include/c++/9/ostream: In substitution of 'template<class _Ostream, class _Tp> typename std::enable_if<std::__and_<std::__not_<std::is_lvalue_reference<_Tp> >, std::__is_convertible_to_basic_ostream<_Ostream>, std::__is_insertable<typename std::__is_convertible_to_basic_ostream<_Tp>::__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<char>&; _Tp = int]':
foo.cc:6:7: required from here
/usr/include/c++/9/ostream:691:5: error: no type named 'type' in 'struct std::enable_if<false, void>'
foo.cc:15:6: error: no match for 'operator>>' (operand types are 'std::ostream' {aka 'std::basic_ostream<char>'} and 'int')
15 | cout>>y>>endl;
| ~~~~^~~
| | |
| | int
| std::ostream {aka std::basic_ostream<char>}
foo.cc:15:6: note: candidate: 'operator>>(int, int)' <built-in>
15 | cout>>y>>endl;
| ~~~~^~~
foo.cc:15:6: note: no known conversion for argument 1 from 'std::ostream' {aka 'std::basic_ostream<char>'} to 'int'
In file included from /usr/include/c++/9/string:56,
from /usr/include/c++/9/bits/locale_classes.h:40,
from /usr/include/c++/9/bits/ios_base.h:41,
from /usr/include/c++/9/ios:42,
from /usr/include/c++/9/ostream:38,
from /usr/include/c++/9/iostream:39,
from foo.cc:1:
/usr/include/c++/9/bits/basic_string.tcc:1466:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&)'
1466 | operator>>(basic_istream<_CharT, _Traits>& __in,
| ^~~~~~~~
/usr/include/c++/9/bits/basic_string.tcc:1466:5: note: template argument deduction/substitution failed:
foo.cc:15:8: note: 'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
15 | cout>>y>>endl;
| ^
In file included from /usr/include/c++/9/istream:991,
from /usr/include/c++/9/iostream:40,
from foo.cc:1:
/usr/include/c++/9/bits/istream.tcc:931:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, _CharT&)'
931 | operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c)
| ^~~~~~~~
/usr/include/c++/9/bits/istream.tcc:931:5: note: template argument deduction/substitution failed:
foo.cc:15:8: note: 'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
15 | cout>>y>>endl;
| ^
In file included from /usr/include/c++/9/iostream:40,
from foo.cc:1:
/usr/include/c++/9/istream:756:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, unsigned char&)'
756 | operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
| ^~~~~~~~
/usr/include/c++/9/istream:756:5: note: template argument deduction/substitution failed:
foo.cc:15:8: note: 'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
15 | cout>>y>>endl;
| ^
In file included from /usr/include/c++/9/iostream:40,
from foo.cc:1:
/usr/include/c++/9/istream:761:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, signed char&)'
761 | operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
| ^~~~~~~~
/usr/include/c++/9/istream:761:5: note: template argument deduction/substitution failed:
foo.cc:15:8: note: 'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
15 | cout>>y>>endl;
| ^
In file included from /usr/include/c++/9/istream:991,
from /usr/include/c++/9/iostream:40,
from foo.cc:1:
/usr/include/c++/9/bits/istream.tcc:963:5: note: candidate: 'template<class _CharT2, class _Traits2> std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&, _CharT2*)'
963 | operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s)
| ^~~~~~~~
/usr/include/c++/9/bits/istream.tcc:963:5: note: template argument deduction/substitution failed:
foo.cc:15:8: note: 'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<_CharT, _Traits>'
15 | cout>>y>>endl;
| ^
In file included from /usr/include/c++/9/iostream:40,
from foo.cc:1:
/usr/include/c++/9/istream:803:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, unsigned char*)'
803 | operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
| ^~~~~~~~
/usr/include/c++/9/istream:803:5: note: template argument deduction/substitution failed:
foo.cc:15:8: note: 'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
15 | cout>>y>>endl;
| ^
In file included from /usr/include/c++/9/iostream:40,
from foo.cc:1:
/usr/include/c++/9/istream:808:5: note: candidate: 'template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, signed char*)'
808 | operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
| ^~~~~~~~
/usr/include/c++/9/istream:808:5: note: template argument deduction/substitution failed:
foo.cc:15:8: note: 'std::ostream' {aka 'std::basic_ostream<char>'} is not derived from 'std::basic_istream<char, _Traits>'
15 | cout>>y>>endl;
| ^
In file included from /usr/include/c++/9/iostream:40,
from foo.cc:1:
/usr/include/c++/9/istream:980:5: note: candidate: 'template<class _Istream, class _Tp> typename std::enable_if<std::__and_<std::__not_<std::is_lvalue_reference<_Tp> >, std::__is_convertible_to_basic_istream<_Istream>, std::__is_extractable<typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type, _Tp&&, void> >::value, typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type>::type std::operator>>(_Istream&&, _Tp&&)'
980 | operator>>(_Istream&& __is, _Tp&& __x)
| ^~~~~~~~
/usr/include/c++/9/istream:980:5: note: template argument deduction/substitution failed:
/usr/include/c++/9/istream: In substitution of 'template<class _Istream, class _Tp> typename std::enable_if<std::__and_<std::__not_<std::is_lvalue_reference<_Tp> >, std::__is_convertible_to_basic_istream<_Istream>, std::__is_extractable<typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type, _Tp&&, void> >::value, typename std::__is_convertible_to_basic_istream<_Tp>::__istream_type>::type std::operator>>(_Istream&&, _Tp&&) [with _Istream = std::basic_ostream<char>&; _Tp = int&]':
foo.cc:15:8: required from here
/usr/include/c++/9/istream:980:5: error: no type named 'type' in 'struct std::enable_if<false, void>'
yty (杨天岳) LV 4
undefined
