foo.cc: In function 'int main()':
foo.cc:6:8: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type {aka std::basic_istream<char>}' and 'const char [2]')
cin>>A>>" ">>B;
~~~~~~^~~~~
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:168:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
operator>>(bool& __n)
^~~~~~~~
/usr/include/c++/7/istream:168:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: cannot bind non-const lvalue reference of type 'bool&' to an rvalue of type 'bool'
cin>>A>>" ">>B;
^~~
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:172:7: note: candidate: std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>] <near match>
operator>>(short& __n);
^~~~~~~~
/usr/include/c++/7/istream:172:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const char*' to 'short int' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(short int)((const char*)" ")' to 'short int&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:175:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
operator>>(unsigned short& __n)
^~~~~~~~
/usr/include/c++/7/istream:175:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const char*' to 'short unsigned int' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(short unsigned int)((const char*)" ")' to 'short unsigned int&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:179:7: note: candidate: std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>] <near match>
operator>>(int& __n);
^~~~~~~~
/usr/include/c++/7/istream:179:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const char*' to 'int' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(int)((const char*)" ")' to 'int&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:182:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
operator>>(unsigned int& __n)
^~~~~~~~
/usr/include/c++/7/istream:182:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const char*' to 'unsigned int' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(unsigned int)((const char*)" ")' to 'unsigned int&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:186:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
operator>>(long& __n)
^~~~~~~~
/usr/include/c++/7/istream:186:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const char*' to 'long int' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(long int)((const char*)" ")' to 'long int&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:190:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
operator>>(unsigned long& __n)
^~~~~~~~
/usr/include/c++/7/istream:190:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const char*' to 'long unsigned int' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(long unsigned int)((const char*)" ")' to 'long unsigned int&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:195:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
operator>>(long long& __n)
^~~~~~~~
/usr/include/c++/7/istream:195:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const char*' to 'long long int' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(long long int)((const char*)" ")' to 'long long int&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:199:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
operator>>(unsigned long long& __n)
^~~~~~~~
/usr/include/c++/7/istream:199:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const char*' to 'long long unsigned int' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(long long unsigned int)((const char*)" ")' to 'long long unsigned int&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:235:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
operator>>(void*& __p)
^~~~~~~~
/usr/include/c++/7/istream:235:7: note: conversion of argument 1 would be ill-formed:
foo.cc:6:10: error: invalid conversion from 'const void*' to 'void*' [-fpermissive]
cin>>A>>" ">>B;
^~~
foo.cc:6:10: error: cannot bind rvalue '(void*)((const void*)((const char*)" "))' to 'void*&'
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:120:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::basic_istream<_CharT, _Traits>::__istream_type& (*)(std::basic_istream<_CharT, _Traits>::__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]
operator>>(__istream_type& (*__pf)(__istream_type&))
^~~~~~~~
/usr/include/c++/7/istream:120:7: note: no known conversion for argument 1 from 'const char [2]' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&) {aka std::basic_istream<char>& (*)(std::basic_istream<char>&)}'
/usr/include/c++/7/istream:124:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::basic_istream<_CharT, _Traits>::__ios_type& (*)(std::basic_istream<_CharT, _Traits>::__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>; std::basic_istream<_CharT, _Traits>::__ios_type = std::basic_ios<char>]
operator>>(__ios_type& (*__pf)(__ios_type&))
^~~~~~~~
/usr/include/c++/7/istream:124:7: note: no known conversion for argument 1 from 'const char [2]' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&) {aka std::basic_ios<char>& (*)(std::basic_ios<char>&)}'
/usr/include/c++/7/istream:131:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]
operator>>(ios_base& (*__pf)(ios_base&))
^~~~~~~~
/usr/include/c++/7/istream:131:7: note: no known conversion for argument 1 from 'const char [2]' to 'std::ios_base& (*)(std::ios_base&)'
/usr/include/c++/7/istream:214:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]
operator>>(float& __f)
^~~~~~~~
/usr/include/c++/7/istream:214:7: note: no known conversion for argument 1 from 'const char [2]' to 'float&'
/usr/include/c++/7/istream:218:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]
operator>>(double& __f)
^~~~~~~~
/usr/include/c++/7/istream:218:7: note: no known conversion for argument 1 from 'const char [2]' to 'double&'
/usr/include/c++/7/istream:222:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>]
operator>>(long double& __f)
^~~~~~~~
/usr/include/c++/7/istream:222:7: note: no known conversion for argument 1 from 'const char [2]' to 'long double&'
/usr/include/c++/7/istream:259:7: note: candidate: std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(std::basic_istream<_CharT, _Traits>::__streambuf_type*) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__streambuf_type = std::basic_streambuf<char>]
operator>>(__streambuf_type* __sb);
^~~~~~~~
/usr/include/c++/7/istream:259:7: note: no known conversion for argument 1 from 'const char [2]' to 'std::basic_istream<char>::__streambuf_type* {aka std::basic_streambuf<char>*}'
In file included from /usr/include/c++/7/string:53:0,
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 foo.cc:1:
/usr/include/c++/7/bits/basic_string.tcc:1465:5: 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>&)
operator>>(basic_istream<_CharT, _Traits>& __in,
^~~~~~~~
/usr/include/c++/7/bits/basic_string.tcc:1465:5: note: template argument deduction/substitution failed:
foo.cc:6:10: note: mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>' and 'const char [2]'
cin>>A>>" ">>B;
^~~
In file included from /usr/include/c++/7/istream:991:0,
from /usr/include/c++/7/iostream:40,
from foo.cc:1:
/usr/include/c++/7/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*)
operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s)
^~~~~~~~
/usr/include/c++/7/bits/istream.tcc:963:5: note: template argument deduction/substitution failed:
foo.cc:6:10: note: deduced conflicting types for parameter '_CharT2' ('char' and 'const char')
cin>>A>>" ">>B;
^~~
In file included from /usr/include/c++/7/istream:991:0,
from /usr/include/c++/7/iostream:40,
from foo.cc:1:
/usr/include/c++/7/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&)
operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c)
^~~~~~~~
/usr/include/c++/7/bits/istream.tcc:931:5: note: template argument deduction/substitution failed:
foo.cc:6:10: note: deduced conflicting types for parameter '_CharT' ('char' and 'const char [2]')
cin>>A>>" ">>B;
^~~
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:756:5: note: candidate: template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, unsigned char&)
operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
^~~~~~~~
/usr/include/c++/7/istream:756:5: note: template argument deduction/substitution failed:
foo.cc:6:10: note: cannot convert '" "' (type 'const char [2]') to type 'unsigned char&'
cin>>A>>" ">>B;
^~~
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:761:5: note: candidate: template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, signed char&)
operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
^~~~~~~~
/usr/include/c++/7/istream:761:5: note: template argument deduction/substitution failed:
foo.cc:6:10: note: cannot convert '" "' (type 'const char [2]') to type 'signed char&'
cin>>A>>" ">>B;
^~~
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:803:5: note: candidate: template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, unsigned char*)
operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
^~~~~~~~
/usr/include/c++/7/istream:803:5: note: template argument deduction/substitution failed:
foo.cc:6:10: note: cannot convert '" "' (type 'const char [2]') to type 'unsigned char*'
cin>>A>>" ">>B;
^~~
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:808:5: note: candidate: template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, signed char*)
operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
^~~~~~~~
/usr/include/c++/7/istream:808:5: note: template argument deduction/substitution failed:
foo.cc:6:10: note: cannot convert '" "' (type 'const char [2]') to type 'signed char*'
cin>>A>>" ">>B;
^~~
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/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&&)
operator>>(_Istream&& __is, _Tp&& __x)
^~~~~~~~
/usr/include/c++/7/istream:980:5: note: template argument deduction/substitution failed:
/usr/include/c++/7/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_istream<char>&; _Tp = const char (&)[2]]':
foo.cc:6:10: required from here
/usr/include/c++/7/istream:980:5: error: no type named 'type' in 'struct std::enable_if<false, std::basic_istream<char>&>'
foo.cc:7:6: error: no match for 'operator>>' (operand types are 'std::ostream {aka std::basic_ostream<char>}' and 'int')
cout>>A*B;
~~~~^~~~~
foo.cc:7:6: note: candidate: operator>>(int, int) <built-in>
foo.cc:7:6: note: no known conversion for argument 1 from 'std::ostream {aka std::basic_ostream<char>}' to 'int'
In file included from /usr/include/c++/7/string:53:0,
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 foo.cc:1:
/usr/include/c++/7/bits/basic_string.tcc:1465:5: 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>&)
operator>>(basic_istream<_CharT, _Traits>& __in,
^~~~~~~~
/usr/include/c++/7/bits/basic_string.tcc:1465:5: note: template argument deduction/substitution failed:
foo.cc:7:10: note: 'std::ostream {aka std::basic_ostream<char>}' is not derived from 'std::basic_istream<_CharT, _Traits>'
cout>>A*B;
^
In file included from /usr/include/c++/7/istream:991:0,
from /usr/include/c++/7/iostream:40,
from foo.cc:1:
/usr/include/c++/7/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*)
operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s)
^~~~~~~~
/usr/include/c++/7/bits/istream.tcc:963:5: note: template argument deduction/substitution failed:
foo.cc:7:10: note: 'std::ostream {aka std::basic_ostream<char>}' is not derived from 'std::basic_istream<_CharT, _Traits>'
cout>>A*B;
^
In file included from /usr/include/c++/7/istream:991:0,
from /usr/include/c++/7/iostream:40,
from foo.cc:1:
/usr/include/c++/7/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&)
operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c)
^~~~~~~~
/usr/include/c++/7/bits/istream.tcc:931:5: note: template argument deduction/substitution failed:
foo.cc:7:10: note: 'std::ostream {aka std::basic_ostream<char>}' is not derived from 'std::basic_istream<_CharT, _Traits>'
cout>>A*B;
^
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:756:5: note: candidate: template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, unsigned char&)
operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
^~~~~~~~
/usr/include/c++/7/istream:756:5: note: template argument deduction/substitution failed:
foo.cc:7:10: note: 'std::ostream {aka std::basic_ostream<char>}' is not derived from 'std::basic_istream<char, _Traits>'
cout>>A*B;
^
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:761:5: note: candidate: template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, signed char&)
operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
^~~~~~~~
/usr/include/c++/7/istream:761:5: note: template argument deduction/substitution failed:
foo.cc:7:10: note: 'std::ostream {aka std::basic_ostream<char>}' is not derived from 'std::basic_istream<char, _Traits>'
cout>>A*B;
^
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:803:5: note: candidate: template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, unsigned char*)
operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
^~~~~~~~
/usr/include/c++/7/istream:803:5: note: template argument deduction/substitution failed:
foo.cc:7:10: note: 'std::ostream {aka std::basic_ostream<char>}' is not derived from 'std::basic_istream<char, _Traits>'
cout>>A*B;
^
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/istream:808:5: note: candidate: template<class _Traits> std::basic_istream<char, _Traits>& std::operator>>(std::basic_istream<char, _Traits>&, signed char*)
operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
^~~~~~~~
/usr/include/c++/7/istream:808:5: note: template argument deduction/substitution failed:
foo.cc:7:10: note: 'std::ostream {aka std::basic_ostream<char>}' is not derived from 'std::basic_istream<char, _Traits>'
cout>>A*B;
^
In file included from /usr/include/c++/7/iostream:40:0,
from foo.cc:1:
/usr/include/c++/7/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&&)
operator>>(_Istream&& __is, _Tp&& __x)
^~~~~~~~
/usr/include/c++/7/istream:980:5: note: template argument deduction/substitution failed:
/usr/include/c++/7/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:7:10: required from here
/usr/include/c++/7/istream:980:5: error: no type named 'type' in 'struct std::enable_if<false, void>'
foo.cc:8:9: error: 'o' was not declared in this scope
return o;
^
202012235陈诺 (2020122陈诺) LV 3
undefined
