/in/foo.cc:21:21: error: declaration of 'operator<<' as non-function
   21 |     friend ostream& operator<<ostream& os, const Complex& c) {
      |                     ^~~~~~~~
/in/foo.cc:21:29: error: expected ';' at end of member declaration
   21 |     friend ostream& operator<<ostream& os, const Complex& c) {
      |                             ^~
      |                               ;
/in/foo.cc:21:44: error: expected unqualified-id before 'const'
   21 |     friend ostream& operator<<ostream& os, const Complex& c) {
      |                                            ^~~~~
/in/foo.cc: In constructor 'Complex::Complex(double, double)':
/in/foo.cc:12:5: error: uninitialized reference member in 'std::ostream&' {aka 'class std::basic_ostream<char>&'} [-fpermissive]
   12 |     Complex(double r = 0, double i = 0) : real(r), imag(i) {}
      |     ^~~~~~~
/in/foo.cc:21:40: note: 'std::ostream& Complex::os' should be initialized
   21 |     friend ostream& operator<<ostream& os, const Complex& c) {
      |                                        ^~
/in/foo.cc: In member function 'void ComplexArray::bubbleSort()':
/in/foo.cc:42:25: error: no matching function for call to 'swap(__gnu_cxx::__alloc_traits<std::allocator<Complex>, Complex>::value_type&, __gnu_cxx::__alloc_traits<std::allocator<Complex>, Complex>::value_type&)'
   42 |                     swap(data[j], data[j + 1]);
      |                     ~~~~^~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/12/bits/exception_ptr.h:43,
                 from /usr/include/c++/12/exception:168,
                 from /usr/include/c++/12/ios:39,
                 from /usr/include/c++/12/ostream:38,
                 from /usr/include/c++/12/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/12/bits/move.h:196:5: note: candidate: 'template<class _Tp> std::_Require<std::__not_<std::__is_tuple_like<_Tp> >, std::is_move_constructible<_Tp>, std::is_move_assignable<_Tp> > std::swap(_Tp&, _Tp&)'
  196 |     swap(_Tp& __a, _Tp& __b)
      |     ^~~~
/usr/include/c++/12/bits/move.h:196:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/12/bits/move.h:57:
/usr/include/c++/12/type_traits: In substitution of 'template<bool _Cond, class _Tp> using __enable_if_t = typename std::enable_if::type [with bool _Cond = false; _Tp = void]':
/usr/include/c++/12/type_traits:2244:11:   required by substitution of 'template<class ... _Cond> using _Require = std::__enable_if_t<std::__and_< <template-parameter-1-1> >::value> [with _Cond = {std::__not_<std::__is_tuple_like<Complex> >, std::is_move_constructible<Complex>, std::is_move_assignable<Complex>}]'
/usr/include/c++/12/bits/move.h:196:5:   required by substitution of 'template<class _Tp> std::_Require<std::__not_<std::__is_tuple_like<_Tp> >, std::is_move_constructible<_Tp>, std::is_move_assignable<_Tp> > std::swap(_Tp&, _Tp&) [with _Tp = Complex]'
/in/foo.cc:42:25:   required from here
/usr/include/c++/12/type_traits:2240:11: error: no type named 'type' in 'struct std::enable_if<false, void>'
 2240 |     using __enable_if_t = typename enable_if<_Cond, _Tp>::type;
      |           ^~~~~~~~~~~~~
/usr/include/c++/12/bits/move.h:220:5: note: candidate: 'template<class _Tp, long unsigned int _Nm> std::__enable_if_t<std::__is_swappable<_Tp>::value> std::swap(_Tp (&)[_Nm], _Tp (&)[_Nm])'
  220 |     swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
      |     ^~~~
/usr/include/c++/12/bits/move.h:220:5: note:   template argument deduction/substitution failed:
/in/foo.cc:42:25: note:   mismatched types '_Tp [_Nm]' and '__gnu_cxx::__alloc_traits<std::allocator<Complex>, Complex>::value_type' {aka 'Complex'}
   42 |                     swap(data[j], data[j + 1]);
      |                     ~~~~^~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/12/bits/stl_algobase.h:64,
                 from /usr/include/c++/12/string:50,
                 from /usr/include/c++/12/bits/locale_classes.h:40,
                 from /usr/include/c++/12/bits/ios_base.h:41,
                 from /usr/include/c++/12/ios:42:
/usr/include/c++/12/bits/stl_pair.h:707:5: note: candidate: 'template<class _T1, class _T2> void std::swap(pair<_T1, _T2>&, pair<_T1, _T2>&)'
  707 |     swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
      |     ^~~~
/usr/include/c++/12/bits/stl_pair.h:707:5: note:   template argument deduction/substitution failed:
/in/foo.cc:42:25: note:   '__gnu_cxx::__alloc_traits<std::allocator<Complex>, Complex>::value_type' {aka 'Complex'} is not derived from 'std::pair<_T1, _T2>'
   42 |                     swap(data[j], data[j + 1]);
      |                     ~~~~^~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/12/string:53:
/usr/include/c++/12/bits/basic_string.h:3845:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> void std::swap(__cxx11::basic_string<_CharT, _Traits, _Alloc>&, __cxx11::basic_string<_CharT, _Traits, _Alloc>&)'
 3845 |     swap(basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~
/usr/include/c++/12/bits/basic_string.h:3845:5: note:   template argument deduction/substitution failed:
/in/foo.cc:42:25: note:   '__gnu_cxx::__alloc_traits<std::allocator<Complex>, Complex>::value_type' {aka 'Complex'} is not derived from 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>'
   42 |                     swap(data[j], data[j + 1]);
      |                     ~~~~^~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/12/vector:64,
                 from /in/foo.cc:3:
/usr/include/c++/12/bits/stl_vector.h:2107:5: note: candidate: 'template<class _Tp, class _Alloc> void std::swap(vector<_Tp, _Alloc>&, vector<_Tp, _Alloc>&)'
 2107 |     swap(vector<_Tp, _Alloc>& __x, vector<_Tp, _Alloc>& __y)
      |     ^~~~
/usr/include/c++/12/bits/stl_vector.h:2107:5: note:   template argument deduction/substitution failed:
/in/foo.cc:42:25: note:   '__gnu_cxx::__alloc_traits<std::allocator<Complex>, Complex>::value_type' {aka 'Complex'} is not derived from 'std::vector<_Tp, _Alloc>'
   42 |                     swap(data[j], data[j + 1]);
      |                     ~~~~^~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc: In member function 'void ComplexArray::print() const':
/in/foo.cc:50:18: error: no match for 'operator<<' (operand types are 'std::ostream' {aka 'std::basic_ostream<char>'} and 'const Complex')
   50 |             cout << c << std::endl;
      |             ~~~~ ^~ ~
      |             |       |
      |             |       const Complex
      |             std::ostream {aka std::basic_ostream<char>}
/usr/include/c++/12/ostream:108:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(__ostream_type& (*)(__ostream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>]'
  108 |       operator<<(__ostream_type& (*__pf)(__ostream_type&))
      |       ^~~~~~~~
/usr/include/c++/12/ostream:108:36: note:   no known conversion for argument 1 from 'const Complex' 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++/12/ostream:117:7: note: candidate: 'std::basic_ostream<_CharT, _Traits>::__ostream_type& std::basic_ostream<_CharT, _Traits>::operator<<(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __ostream_type = std::basic_ostream<char>; __ios_type = std::basic_ios<char>]'
  117 |       operator<<(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/12/ostream:117:32: note:   no known conversion for argument 1 from 'const Complex' 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++/12/ostream:127:7: note: candidate: 'std::basic_o