Как вывести переменную класса boost :: any?

@olanro-ux · Регистрация: 08.12.2020

Author24 — интернет-сервис помощи студентам

Впрнцп, я пытаюсь сделать что то подобное:

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C++
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#include <boost/any.hpp>
 
#include "iostream"
 
#include "fstream"
 
class meth {
  public:
    boost::any console;
  std::ofstream out;
  public:
    meth() {}
  template < typename T1 >
    auto input(T1 & consolen) {
      consolen = "wellldonw";
      printer(console);
    }
 
  template < typename T >
    auto printer(T & t) {
      std::cout << t;
    }
};
 
int main() {
  meth methode;
  methode.input(methode.console);
}

Но увы, делать cout any я видимо не могу:

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PowerShell
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test.cpp: In instantiation of ‘auto meth::printer(T&) [with T = boost::any]’:
test.cpp:16:9:   required from ‘auto meth::input(T1&) [with T1 = boost::any]’
test.cpp:28:30:   required from here
test.cpp:22:15: error: no match for ‘operator<<’ (operand types are ‘std::ostream’ {aka ‘std::basic_ostream<char>’} and ‘boost::any’)
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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&))
      |       ^~~~~~~~
/usr/include/c++/10/ostream:108:36: note:   no known conversion for argument 1 from ‘boost::any’ 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&))
      |                  ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/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&))
      |       ^~~~~~~~
/usr/include/c++/10/ostream:117:32: note:   no known conversion for argument 1 from ‘boost::any’ 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&))
      |                  ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
/usr/include/c++/10/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&))
      |       ^~~~~~~~
/usr/include/c++/10/ostream:127:30: note:   no known conversion for argument 1 from ‘boost::any’ to ‘std::ios_base& (*)(std::ios_base&)’
  127 |       operator<<(ios_base& (*__pf) (ios_base&))
      |                  ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:166:23: note:   no known conversion for argument 1 from ‘boost::any’ to ‘long int’
  166 |       operator<<(long __n)
      |                  ~~~~~^~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:170:32: note:   no known conversion for argument 1 from ‘boost::any’ to ‘long unsigned int’
  170 |       operator<<(unsigned long __n)
      |                  ~~~~~~~~~~~~~~^~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:174:23: note:   no known conversion for argument 1 from ‘boost::any’ to ‘bool’
  174 |       operator<<(bool __n)
      |                  ~~~~~^~~
In file included from /usr/include/c++/10/ostream:784,
                 from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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>::
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/bits/ostream.tcc:92:22: note:   no known conversion for argument 1 from ‘boost::any’ to ‘short int’
   92 |     operator<<(short __n)
      |                ~~~~~~^~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:181:33: note:   no known conversion for argument 1 from ‘boost::any’ to ‘short unsigned int’
  181 |       operator<<(unsigned short __n)
      |                  ~~~~~~~~~~~~~~~^~~
In file included from /usr/include/c++/10/ostream:784,
                 from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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>::
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/bits/ostream.tcc:106:20: note:   no known conversion for argument 1 from ‘boost::any’ to ‘int’
  106 |     operator<<(int __n)
      |                ~~~~^~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:192:31: note:   no known conversion for argument 1 from ‘boost::any’ to ‘unsigned int’
  192 |       operator<<(unsigned int __n)
      |                  ~~~~~~~~~~~~~^~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:201:28: note:   no known conversion for argument 1 from ‘boost::any’ to ‘long long int’
  201 |       operator<<(long long __n)
      |                  ~~~~~~~~~~^~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:205:37: note:   no known conversion for argument 1 from ‘boost::any’ to ‘long long unsigned int’
  205 |       operator<<(unsigned long long __n)
      |                  ~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:220:25: note:   no known conversion for argument 1 from ‘boost::any’ to ‘double’
  220 |       operator<<(double __f)
      |                  ~~~~~~~^~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:224:24: note:   no known conversion for argument 1 from ‘boost::any’ to ‘float’
  224 |       operator<<(float __f)
      |                  ~~~~~~^~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:232:30: note:   no known conversion for argument 1 from ‘boost::any’ to ‘long double’
  232 |       operator<<(long double __f)
      |                  ~~~~~~~~~~~~^~~
/usr/include/c++/10/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)
      |       ^~~~~~~~
/usr/include/c++/10/ostream:245:30: note:   no known conversion for argument 1 from ‘boost::any’ to ‘const void*’
  245 |       operator<<(const void* __p)
      |                  ~~~~~~~~~~~~^~~
In file included from /usr/include/c++/10/ostream:784,
                 from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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>::
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/10/bits/ostream.tcc:120:34: note:   no known conversion for argument 1 from ‘boost::any’ to ‘std::basic_ostream<char>::__streambuf_type*’ {aka ‘std::basic_streambuf<char>*’}
  120 |     operator<<(__streambuf_type* __sbin)
      |                ~~~~~~~~~~~~~~~~~~^~~~~~
In file included from /usr/include/boost/throw_exception.hpp:23,
                 from /usr/include/boost/type_index/stl_type_index.hpp:33,
                 from /usr/include/boost/type_index.hpp:29,
                 from /usr/include/boost/any.hpp:18,
                 from test.cpp:1:
/usr/include/boost/assert/source_location.hpp:58:55: note: candidate: ‘template<class E, class T> std::basic_ostream<_CharT, _Traits>& boost::operator<<(std::basic_ostream<_CharT, _Traits>&, const boost::source_location&)’
   58 | template<class E, class T> std::basic_ostream<E, T> & operator<<( std::basic_ostream<E, T> & os, source_location const & loc )
      |                                                       ^~~~~~~~
/usr/include/boost/assert/source_location.hpp:58:55: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘const boost::source_location&’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/string:55,
                 from /usr/include/boost/type_index/type_index_facade.hpp:14,
                 from /usr/include/boost/type_index/stl_type_index.hpp:22,
                 from /usr/include/boost/type_index.hpp:29,
                 from /usr/include/boost/any.hpp:18,
                 from test.cpp:1:
/usr/include/c++/10/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,
      |     ^~~~~~~~
/usr/include/c++/10/bits/basic_string.h:6468:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   ‘boost::any’ is not derived from ‘const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/bits/ios_base.h:46,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/ostream:38,
                 from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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)
      |     ^~~~~~~~
/usr/include/c++/10/system_error:262:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘const std::error_code&’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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++/10/ostream:506:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   deduced conflicting types for parameter ‘_CharT’ (‘char’ and ‘boost::any’)
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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++/10/ostream:511:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘char’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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++/10/ostream:517:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘char’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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++/10/ostream:523:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘signed char’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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++/10/ostream:528:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘unsigned char’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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)
      |     ^~~~~~~~
/usr/include/c++/10/ostream:589:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   mismatched types ‘const _CharT*’ and ‘boost::any’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/ostream:784,
                 from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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++/10/bits/ostream.tcc:321:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘const char*’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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)
      |     ^~~~~~~~
/usr/include/c++/10/ostream:606:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘const char*’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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)
      |     ^~~~~~~~
/usr/include/c++/10/ostream:619:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘const signed char*’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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)
      |     ^~~~~~~~
/usr/include/c++/10/ostream:624:5: note:   template argument deduction/substitution failed:
test.cpp:22:15: note:   cannot convert ‘t’ (type ‘boost::any’) to type ‘const unsigned char*’
   22 |   std :: cout << t;
      |   ~~~~~~~~~~~~^~~~
In file included from /usr/include/c++/10/iostream:39,
                 from test.cpp:3:
/usr/include/c++/10/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)
      |     ^~~~~~~~
/usr/include/c++/10/ostream:773:5: note:   template argument deduction/substitution failed:
/usr/include/c++/10/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 = boost::any]’:
test.cpp:22:15:   required from ‘auto meth::printer(T&) [with T = boost::any]’
test.cpp:16:9:   required from ‘auto meth::input(T1&) [with T1 = boost::any]’
test.cpp:28:30:   required from here
/usr/include/c++/10/ostream:773:5: error: no type named ‘type’ in ‘struct std::enable_if<false, std::basic_ostream<char>&>’

Сразу говорю, менять any на int, string и тд ради одного cout я не хочу.

Так вот вопрос, как вывести any type?

@GbaLog- · 12.04.2022, 06:53

а как ты себе это представляешь?
что выводить, когда там неизвестно что лежит?
единственный вариант - это получить переменную с типом, который там внутри лежит и её уже вывести.

@hoggy · 18.04.2022, 13:28

Сообщение от GbaLog-

а как ты себе это представляешь?
что выводить, когда там неизвестно что лежит?

std::any прекрасно знает, что у него там лежит.
в его основе лежит идиома type erasure
к сожалению, из коробки вывод в поток не предусмотрен.

Сообщение от olanro-ux

как вывести any type?

можно задействовать type erasure,
и просто доработать недостающую функциональность:

https://rextester.com/MNIL91254

C++
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#include <iostream>
#include <cassert>
#include <any>
 
struct iout
{
    virtual ~iout(){}
    virtual std::ostream& out(std::ostream& out, const std::any& data) const = 0;
};
 
template<class t>
struct tout: iout
{
    virtual std::ostream& out(std::ostream& out, const std::any& data) const override
    {
        const auto p = std::any_cast<const t>(&data);
        assert(p);
        out << *p << '\n';
        return out;
    }
};
 
struct meth 
{
    std::any console;
    char type_erasure[sizeof(iout)];
    
    meth(): console(), type_erasure() {}
    
    template<typename t> void emplace(t&& src) 
    {
        console = std::forward<t>(src);
        new (type_erasure) tout<t>();
    }
    
    template<typename t, size_t n> void emplace(t (&src)[n]) 
    {
        console = std::string(src);
        new (type_erasure) tout<std::string>();
    }
    
    void print() const
    {
        assert(console.has_value());
        const iout* view = reinterpret_cast<const iout*>(type_erasure);
        assert(view);
        view->out(std::cout, console);
    }
};
 
int main() 
{
    meth methode;
    
    methode.emplace(33);
    methode.print();
    
    methode.emplace(true);
    methode.print();
    
    methode.emplace("hello");
    methode.print();    
}

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@GbaLog- Любитель чаепитий 3744 / 1800 / 566 Регистрация: 24.08.2014 Сообщений: 6,018 Записей в блоге: 1
	12.04.2022, 06:53
	а как ты себе это представляешь? что выводить, когда там неизвестно что лежит? единственный вариант - это получить переменную с типом, который там внутри лежит и её уже вывести. 0

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Как вывести переменную класса boost :: any?

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