foo.cc: In function 'int main()':
foo.cc:8:5: error: no match for 'operator<<' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'int')
8 | cin<<a<<b;
| ~~~^~~
| | |
| | int
| std::istream {aka std::basic_istream<char>}
foo.cc:8:5: note: candidate: 'operator<<(int, int)' <built-in>
8 | cin<<a<<b;
| ~~~^~~
foo.cc:8:5: 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:6416:5: 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>&)'
6416 | operator<<(basic_ostream<_CharT, _Traits>& __os,
| ^~~~~~~~
/usr/include/c++/9/bits/basic_string.h:6416:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
8 | cin<<a<<b;
| ^
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:8:7: required from here
/usr/include/c++/9/ostream:691:5: error: no type named 'type' in 'struct std::enable_if<false, void>'
In file included from foo.cc:3:
/usr/include/c++/9/iomanip:79:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::_Resetiosflags)'
79 | operator<<(basic_ostream<_CharT, _Traits>& __os, _Resetiosflags __f)
| ^~~~~~~~
/usr/include/c++/9/iomanip:79:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
In file included from foo.cc:3:
/usr/include/c++/9/iomanip:109:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::_Setiosflags)'
109 | operator<<(basic_ostream<_CharT, _Traits>& __os, _Setiosflags __f)
| ^~~~~~~~
/usr/include/c++/9/iomanip:109:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
In file included from foo.cc:3:
/usr/include/c++/9/iomanip:143:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::_Setbase)'
143 | operator<<(basic_ostream<_CharT, _Traits>& __os, _Setbase __f)
| ^~~~~~~~
/usr/include/c++/9/iomanip:143:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
In file included from foo.cc:3:
/usr/include/c++/9/iomanip:178:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::_Setfill<_CharT>)'
178 | operator<<(basic_ostream<_CharT, _Traits>& __os, _Setfill<_CharT> __f)
| ^~~~~~~~
/usr/include/c++/9/iomanip:178:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
In file included from foo.cc:3:
/usr/include/c++/9/iomanip:208:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::_Setprecision)'
208 | operator<<(basic_ostream<_CharT, _Traits>& __os, _Setprecision __f)
| ^~~~~~~~
/usr/include/c++/9/iomanip:208:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
In file included from foo.cc:3:
/usr/include/c++/9/iomanip:238:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::_Setw)'
238 | operator<<(basic_ostream<_CharT, _Traits>& __os, _Setw __f)
| ^~~~~~~~
/usr/include/c++/9/iomanip:238:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
In file included from foo.cc:3:
/usr/include/c++/9/iomanip:311:5: note: candidate: 'template<class _CharT, class _Traits, class _MoneyT> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::_Put_money<_MoneyT>)'
311 | operator<<(basic_ostream<_CharT, _Traits>& __os, _Put_money<_MoneyT> __f)
| ^~~~~~~~
/usr/include/c++/9/iomanip:311:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
In file included from foo.cc:3:
/usr/include/c++/9/iomanip:363:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, std::_Put_time<_CharT>)'
363 | operator<<(basic_ostream<_CharT, _Traits>& __os, _Put_time<_CharT> __f)
| ^~~~~~~~
/usr/include/c++/9/iomanip:363:5: note: template argument deduction/substitution failed:
foo.cc:8:7: note: 'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
8 | cin<<a<<b;
| ^
2020223陆王涵 (陆王涵) LV 6
undefined
