Language: C++

#include<bits/stdc++.h>
using namespace std;
int main(){
  std::sync_with_stdio(false); cin.tie(false); cout.tie(false);
  char input;
  cin<<input;
  if(input>='A' && input<='Z') cout<<'A'<<'\n';
    else cout<<'a'<<'\n';
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:8: error: 'sync_with_stdio' is not a member of 'std'
    4 |   std::sync_with_stdio(false); cin.tie(false); cout.tie(false);
      |        ^~~~~~~~~~~~~~~
a.cc:4:39: error: no matching function for call to 'std::basic_istream<char>::tie(bool)'
    4 |   std::sync_with_stdio(false); cin.tie(false); cout.tie(false);
      |                                ~~~~~~~^~~~~~~
In file included from /usr/include/c++/14/ios:46,
                 from /usr/include/c++/14/istream:40,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:1:
/usr/include/c++/14/bits/basic_ios.h:299:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>* std::basic_ios<_CharT, _Traits>::tie() const [with _CharT = char; _Traits = std::char_traits<char>]'
  299 |       tie() const
      |       ^~~
/usr/include/c++/14/bits/basic_ios.h:299:7: note:   candidate expects 0 arguments, 1 provided
/usr/include/c++/14/bits/basic_ios.h:311:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>* std::basic_ios<_CharT, _Traits>::tie(std::basic_ostream<_CharT, _Traits>*) [with _CharT = char; _Traits = std::char_traits<char>]'
  311 |       tie(basic_ostream<_CharT, _Traits>* __tiestr)
      |       ^~~
/usr/include/c++/14/bits/basic_ios.h:311:43: note:   no known conversion for argument 1 from 'bool' to 'std::basic_ostream<char>*'
  311 |       tie(basic_ostream<_CharT, _Traits>* __tiestr)
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
a.cc:4:56: error: no matching function for call to 'std::basic_ostream<char>::tie(bool)'
    4 |   std::sync_with_stdio(false); cin.tie(false); cout.tie(false);
      |                                                ~~~~~~~~^~~~~~~
/usr/include/c++/14/bits/basic_ios.h:299:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>* std::basic_ios<_CharT, _Traits>::tie() const [with _CharT = char; _Traits = std::char_traits<char>]'
  299 |       tie() const
      |       ^~~
/usr/include/c++/14/bits/basic_ios.h:299:7: note:   candidate expects 0 arguments, 1 provided
/usr/include/c++/14/bits/basic_ios.h:311:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>* std::basic_ios<_CharT, _Traits>::tie(std::basic_ostream<_CharT, _Traits>*) [with _CharT = char; _Traits = std::char_traits<char>]'
  311 |       tie(basic_ostream<_CharT, _Traits>* __tiestr)
      |       ^~~
/usr/include/c++/14/bits/basic_ios.h:311:43: note:   no known conversion for argument 1 from 'bool' to 'std::basic_ostream<char>*'
  311 |       tie(basic_ostream<_CharT, _Traits>* __tiestr)
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
a.cc:6:6: error: no match for 'operator<<' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'char')
    6 |   cin<<input;
      |   ~~~^~~~~~~
      |   |    |
      |   |    char
      |   std::istream {aka std::basic_istream<char>}
a.cc:6:6: note: candidate: 'operator<<(int, int)' (built-in)
    6 |   cin<<input;
      |   ~~~^~~~~~~
a.cc:6:6: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'int'
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181:
/usr/include/c++/14/bits/regex.h:1715:5: note: candidate: 'template<class _Ch_type, class _Ch_traits, class _Bi_iter> std::basic_ostream<_CharT, _Traits>& std::__cxx11::operator<<(std::basic_ostream<_CharT, _Traits>&, const sub_match<_Bi_iter>&)'
 1715 |     operator<<(basic_ostream<_Ch_type, _Ch_traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1715:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:41:
/usr/include/c++/14/cstddef:125:5: note: candidate: 'template<class _IntegerType> constexpr std::__byte_op_t<_IntegerType> std::operator<<(byte, _IntegerType)'
  125 |     operator<<(byte __b, _IntegerType __shift) noexcept
      |     ^~~~~~~~
/usr/include/c++/14/cstddef:125:5: note:   template argument deduction/substitution failed:
a.cc:6:3: note:   cannot convert 'std::cin' (type 'std::istream' {aka 'std::basic_istream<char>'}) to type 'std::byte'
    6 |   cin<<input;
      |   ^~~
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/string_view:763:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, basic_string_view<_CharT, _Traits>)'
  763 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:763:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
/usr/include/c++/14/bits/basic_string.h:4077:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 4077 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:4077:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
/usr/include/c++/14/bitset:1687:5: note: candidate: 'template<class _CharT, class _Traits, long unsigned int _Nb> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const bitset<_Nb>&)'
 1687 |     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bitset:1687:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
In file included from /usr/include/c++/14/bits/ios_base.h:46,
                 from /usr/include/c++/14/streambuf:43,
                 from /usr/include/c++/14/bits/streambuf_iterator.h:35,
                 from /usr/include/c++/14/iterator:66,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:54:
/usr/include/c++/14/system_error:339:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const error_code&)'
  339 |     operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
      |     ^~~~~~~~
/usr/include/c++/14/system_error:339:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
In file included from /usr/include/c++/14/memory:80,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:56:
/usr/include/c++/14/bits/shared_ptr.h:70:5: note: candidate: 'template<class _Ch, class _Tr, class _Tp, __gnu_cxx::_Lock_policy _Lp> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const __shared_ptr<_Tp, _Lp>&)'
   70 |     operator<<(std::basic_ostream<_Ch, _Tr>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bits/shared_ptr.h:70:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
In file included from /usr/include/c++/14/istream:41:
/usr/include/c++/14/ostream:563:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, _CharT)'
  563 |     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:563:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
/usr/include/c++/14/ostream:573:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, char)'
  573 |     operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:573:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<_CharT, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
/usr/include/c++/14/ostream:579:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, char)'
  579 |     operator<<(basic_ostream<char, _Traits>& __out, char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:579:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'std::basic_ostream<char, _Traits>'
    6 |   cin<<input;
      |        ^~~~~
/usr/include/c++/14/ostream:590:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, signed char)'
  590 |     operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:590:5: note:   template argument deduction/substitution failed:
a.cc:6:8: note:   'std::istream'