Language: C++

#include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for(int i = 0; i < n; i++)
#define COUT(x) cout<<(x)<<endl
#define dump(x)  cout << #x << " = " << (x) << endl;
using ll = long long;
using P = pair<int,int>;
using Graph = vector<vector<int>>;
using M = map<int,int>;
using PQ = priority_queue<int>;
using PQG = priority_queue<int, vector<int>, greater<int>>;
const int INF = 1e9;
const int MOD = 1e9+7;
const ll LINF = 1e18;

int main() {
  int a,b,c; cin >> a >> b >> c;
  cout << a^b^c;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:18:12: error: no match for 'operator^' (operand types are 'std::basic_ostream<char>' and 'int')
   18 |   cout << a^b^c;
      |   ~~~~~~~~~^~
      |        |    |
      |        |    int
      |        std::basic_ostream<char>
a.cc:18:12: note: candidate: 'operator^(int, int)' (built-in)
   18 |   cout << a^b^c;
      |   ~~~~~~~~~^~
a.cc:18:12: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'int'
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:1:
/usr/include/c++/14/bitset:1577:5: note: candidate: 'template<long unsigned int _Nb> std::bitset<_Nb> std::operator^(const bitset<_Nb>&, const bitset<_Nb>&)'
 1577 |     operator^(const bitset<_Nb>& __x, const bitset<_Nb>& __y) _GLIBCXX_NOEXCEPT
      |     ^~~~~~~~
/usr/include/c++/14/bitset:1577:5: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   'std::basic_ostream<char>' is not derived from 'const std::bitset<_Nb>'
   18 |   cout << a^b^c;
      |             ^
In file included from /usr/include/c++/14/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166:
/usr/include/c++/14/bits/valarray_after.h:410:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__bitwise_xor, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__bitwise_xor, typename _Dom1::value_type>::result_type> std::operator^(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  410 |     _DEFINE_EXPR_BINARY_OPERATOR(^, struct std::__bitwise_xor)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:410:5: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   'std::basic_ostream<char>' is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   18 |   cout << a^b^c;
      |             ^
/usr/include/c++/14/bits/valarray_after.h:410:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__bitwise_xor, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__bitwise_xor, typename _Dom1::value_type>::result_type> std::operator^(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  410 |     _DEFINE_EXPR_BINARY_OPERATOR(^, struct std::__bitwise_xor)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:410:5: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   'std::basic_ostream<char>' is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   18 |   cout << a^b^c;
      |             ^
/usr/include/c++/14/bits/valarray_after.h:410:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__bitwise_xor, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__bitwise_xor, typename _Dom1::value_type>::result_type> std::operator^(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  410 |     _DEFINE_EXPR_BINARY_OPERATOR(^, struct std::__bitwise_xor)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:410:5: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
   18 |   cout << a^b^c;
      |             ^
/usr/include/c++/14/bits/valarray_after.h:410:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__bitwise_xor, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__bitwise_xor, typename _Dom1::value_type>::result_type> std::operator^(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  410 |     _DEFINE_EXPR_BINARY_OPERATOR(^, struct std::__bitwise_xor)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:410:5: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   'std::basic_ostream<char>' is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   18 |   cout << a^b^c;
      |             ^
/usr/include/c++/14/bits/valarray_after.h:410:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__bitwise_xor, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__bitwise_xor, typename _Dom1::value_type>::result_type> std::operator^(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  410 |     _DEFINE_EXPR_BINARY_OPERATOR(^, struct std::__bitwise_xor)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:410:5: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
   18 |   cout << a^b^c;
      |             ^
/usr/include/c++/14/valarray:1201:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__bitwise_xor, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__bitwise_xor, _Tp>::result_type> std::operator^(const valarray<_Tp>&, const valarray<_Tp>&)'
 1201 | _DEFINE_BINARY_OPERATOR(^, __bitwise_xor)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1201:1: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   'std::basic_ostream<char>' is not derived from 'const std::valarray<_Tp>'
   18 |   cout << a^b^c;
      |             ^
/usr/include/c++/14/valarray:1201:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__bitwise_xor, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__bitwise_xor, _Tp>::result_type> std::operator^(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
 1201 | _DEFINE_BINARY_OPERATOR(^, __bitwise_xor)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1201:1: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   'std::basic_ostream<char>' is not derived from 'const std::valarray<_Tp>'
   18 |   cout << a^b^c;
      |             ^
/usr/include/c++/14/valarray:1201:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__bitwise_xor, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__bitwise_xor, _Tp>::result_type> std::operator^(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
 1201 | _DEFINE_BINARY_OPERATOR(^, __bitwise_xor)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1201:1: note:   template argument deduction/substitution failed:
a.cc:18:13: note:   mismatched types 'const std::valarray<_Tp>' and 'int'
   18 |   cout << a^b^c;
      |             ^
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:41:
/usr/include/c++/14/cstddef:146:3: note: candidate: 'constexpr std::byte std::operator^(byte, byte)'
  146 |   operator^(byte __l, byte __r) noexcept
      |   ^~~~~~~~
/usr/include/c++/14/cstddef:146:18: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::byte'
  146 |   operator^(byte __l, byte __r) noexcept
      |             ~~~~~^~~
In file included 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/bits/ios_base.h:94:3: note: candidate: 'constexpr std::_Ios_Fmtflags std::operator^(_Ios_Fmtflags, _Ios_Fmtflags)'
   94 |   operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:94:27: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::_Ios_Fmtflags'
   94 |   operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:144:3: note: candidate: 'constexpr std::_Ios_Openmode std::operator^(_Ios_Openmode, _Ios_Openmode)'
  144 |   operator^(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:144:27: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::_Ios_Openmode'
  144 |   operator^(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:191:3: note: candidate: 'constexpr std::_Ios_Iostate std::operator^(_Ios_Iostate, _Ios_Iostate)'
  191 |   operator^(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:191:26: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::_Ios_Iostate'
  191 |   operator^(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~^~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:176:
/usr/include/c++/14/future:170:20: note: candidate: 'constexpr std::launch std::operator^(launch, launch)'
  170 |   constexpr launch operator^(launch __x, launch __y) noexcept
      |                    ^~~~~~~~
/usr/include/c++/14/future:170:37: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::launch'
  170 |   constexpr launch operator^(launch __x, launch __y) noexcept
      |                              ~~~~~~~^~~
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:198:
/usr/include/c++/14/charconv:637:3: note: candidate: 'constexpr std::chars_format std::operator^(chars_format, chars_format)'
  637 |   operator^(chars_format __lhs, chars_format __rhs) noexcept
      |   ^~~~~~~~
/usr/include/c++/14/charconv:637:26: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::chars_format'
  637 |   operator^(chars_format __lhs, chars_format __rhs) noexcept
      |             ~~~~~~~~~~~~~^~~~~