STL的set有test_and_set功能
作者：互联网
test_and_set是这个意思：
/*
UINT32& u = hb[h >> 5];
const UINT32 m = 1 << (h & 0x1f);
const UINT32 seen = u & m;
u |= m; // test_and_set
*/
#include <iostream>
#include <set>
using namespace std;
int main() {
set<int> s;
pair<set<int>::iterator,bool> p = s.insert(1);
cout << p.second << endl;
p = s.insert(1);
cout << p.second << endl;
cout << s.size() << endl;
}
http://www.cplusplus.com/reference/set/set/insert/
一句 cout << p，五颜六色的错误信息爆屏，正好250行:
test.cpp: In function 'int main()':
test.cpp:17:7: error: no match for 'operator<<' (operand types are 'std::ostream' {aka 'std::basic_ostream<char>'} and 'std::pair<std::_Rb_tree_const_iterator<int>, bool>')
17 | cout << p;
| ~~~~ ^~ ~
| | |
| | std::pair<std::_Rb_tree_const_iterator<int>, bool>
| std::ostream {aka std::basic_ostream<char>}
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:108:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__ostream_type& (*)(std::basic_ostream<_CharT, _Traits>::__ostream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
108 | operator<<(__ostream_type& (*__pf)(__ostream_type&))
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:108:36: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'std::basic_ostream<char>::__ostream_type& (*)(std::basic_ostream<char>::__ostream_type&)' {aka 'std::basic_ostream<char>& (*)(std::basic_ostream<char>&)'}
108 | operator<<(__ostream_type& (*__pf)(__ostream_type&))
| ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:117:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__ios_type& (*)(std::basic_ostream<_CharT, _Traits>::__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>; std::basic_ostream<_CharT, _Traits>::__ios_type = std::basic_ios<char>]'
117 | operator<<(__ios_type& (*__pf)(__ios_type&))
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:117:32: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'std::basic_ostream<char>::__ios_type& (*)(std::basic_ostream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'}
117 | operator<<(__ios_type& (*__pf)(__ios_type&))
| ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:127:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
127 | operator<<(ios_base& (*__pf) (ios_base&))
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:127:30: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'std::ios_base& (*)(std::ios_base&)'
127 | operator<<(ios_base& (*__pf) (ios_base&))
| ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:166:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
166 | operator<<(long __n)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:166:23: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'long int'
166 | operator<<(long __n)
| ~~~~~^~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:170:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
170 | operator<<(unsigned long __n)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:170:32: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'long unsigned int'
170 | operator<<(unsigned long __n)
| ~~~~~~~~~~~~~~^~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:174:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(bool) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
174 | operator<<(bool __n)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:174:23: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'bool'
174 | operator<<(bool __n)
| ~~~~~^~~
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:784,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ostream.tcc:91:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(short int) [with _CharT = char; _Traits = std::char_traits<char>]'
91 | basic_ostream<_CharT, _Traits>::
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ostream.tcc:92:22: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'short int'
92 | operator<<(short __n)
| ~~~~~~^~~
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:181:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(short unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
181 | operator<<(unsigned short __n)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:181:33: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'short unsigned int'
181 | operator<<(unsigned short __n)
| ~~~~~~~~~~~~~~~^~~
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:784,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ostream.tcc:105:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(int) [with _CharT = char; _Traits = std::char_traits<char>]'
105 | basic_ostream<_CharT, _Traits>::
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ostream.tcc:106:20: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'int'
106 | operator<<(int __n)
| ~~~~^~~
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:192:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
192 | operator<<(unsigned int __n)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:192:31: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'unsigned int'
192 | operator<<(unsigned int __n)
| ~~~~~~~~~~~~~^~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:201:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
201 | operator<<(long long __n)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:201:28: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'long long int'
201 | operator<<(long long __n)
| ~~~~~~~~~~^~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:205:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long long unsigned int) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
205 | operator<<(unsigned long long __n)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:205:37: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'long long unsigned int'
205 | operator<<(unsigned long long __n)
| ~~~~~~~~~~~~~~~~~~~^~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:220:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(double) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
220 | operator<<(double __f)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:220:25: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'double'
220 | operator<<(double __f)
| ~~~~~~~^~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:224:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(float) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
224 | operator<<(float __f)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:224:24: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'float'
224 | operator<<(float __f)
| ~~~~~~^~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:232:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(long double) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
232 | operator<<(long double __f)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:232:30: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'long double'
232 | operator<<(long double __f)
| ~~~~~~~~~~~~^~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:245:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(const void*) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__ostream_type = std::basic_ostream<char>]'
245 | operator<<(const void* __p)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:245:30: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'const void*'
245 | operator<<(const void* __p)
| ~~~~~~~~~~~~^~~
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:784,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ostream.tcc:119:5: note: candidate: 'std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator<<(std::basic_ostream<_CharT, _Traits>::__streambuf_type*) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_ostream<_CharT, _Traits>::__streambuf_type = std::basic_streambuf<char>]'
119 | basic_ostream<_CharT, _Traits>::
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ostream.tcc:120:34: note: no known conversion for argument 1 from 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' to 'std::basic_ostream<char>::__streambuf_type*' {aka 'std::basic_streambuf<char>*'}
120 | operator<<(__streambuf_type* __sbin)
| ~~~~~~~~~~~~~~~~~~^~~~~~
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/string:55,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/locale_classes.h:40,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ios_base.h:41,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ios:42,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:38,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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,
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/basic_string.h:6468:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: 'std::pair<std::_Rb_tree_const_iterator<int>, bool>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ios_base.h:46,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ios:42,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:38,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/system_error:262:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'const std::error_code&'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:506:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: deduced conflicting types for parameter '_CharT' ('char' and 'std::pair<std::_Rb_tree_const_iterator<int>, bool>')
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:511:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'char'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:517:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'char'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:523:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'signed char'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:528:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'unsigned char'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:589:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(std::basic_ostream<_CharT, _Traits>&, const _CharT*)'
589 | operator<<(basic_ostream<_CharT, _Traits>& ___out, const _CharT* __s)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:589:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: mismatched types 'const _CharT*' and 'std::pair<std::_Rb_tree_const_iterator<int>, bool>'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:784,
from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/bits/ostream.tcc:321:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'const char*'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:606:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const char*)'
606 | operator<<(basic_ostream<char, _Traits>& ___out, const char* __s)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:606:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'const char*'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:619:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const signed char*)'
619 | operator<<(basic_ostream<char, _Traits>& ___out, const signed char* __s)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:619:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'const signed char*'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:624:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(std::basic_ostream<char, _Traits>&, const unsigned char*)'
624 | operator<<(basic_ostream<char, _Traits>& ___out, const unsigned char* __s)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:624:5: note: template argument deduction/substitution failed:
test.cpp:17:10: note: cannot convert 'p' (type 'std::pair<std::_Rb_tree_const_iterator<int>, bool>') to type 'const unsigned char*'
17 | cout << p;
| ^
In file included from d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/iostream:39,
from test.cpp:7:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:773:5: 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&)'
773 | operator<<(_Ostream&& __os, const _Tp& __x)
| ^~~~~~~~
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:773:5: note: template argument deduction/substitution failed:
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/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_ostream<char>&; _Tp = std::pair<std::_Rb_tree_const_iterator<int>, bool>]':
test.cpp:17:10: required from here
d:/gcc/lib/gcc/mingw32/10.3.0/include/c++/ostream:773:5: error: no type named 'type' in 'struct std::enable_if<false, std::basic_ostream<char>&>'
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标签：std,__,set,STL,operator,ostream,basic,test,type 来源： https://www.cnblogs.com/funwithwords/p/15705820.html