/in/ex6.cpp:35:46: error: 'BinaryTree& operator=(const BinaryTree&)' must be a nonstatic member function
 BinaryTree &operator=(const BinaryTree &other)
                                              ^
/in/ex6.cpp: In function 'std::ostream& operator<<(std::ostream&, const BinaryTree&)':
/in/ex6.cpp:97:6: error: no match for 'operator=' (operand types are 'std::ostream {aka std::basic_ostream<char>}' and 'const char [1]')
   os="";
      ^~
In file included from /usr/include/c++/7/iostream:39:0,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/ostream:402:7: note: candidate: std::basic_ostream<_CharT, _Traits>& std::basic_ostream<_CharT, _Traits>::operator=(std::basic_ostream<_CharT, _Traits>&&) [with _CharT = char; _Traits = std::char_traits<char>]
       operator=(basic_ostream&& __rhs)
       ^~~~~~~~
/usr/include/c++/7/ostream:402:7: note:   no known conversion for argument 1 from 'const char [1]' to 'std::basic_ostream<char>&&'
/in/ex6.cpp:100:33: error: base operand of '->' has non-pointer type 'const BinaryTree'
  BinaryTree left=BinaryTree(tree->root->left);
                                 ^~
/in/ex6.cpp:101:34: error: base operand of '->' has non-pointer type 'const BinaryTree'
  BinaryTree right=BinaryTree(tree->root->right);
                                  ^~
/in/ex6.cpp:102:15: error: 'class BinaryTree' has no member named 'operator<<'; did you mean 'operator=='?
  left.operator<<(&os, &tree);
               ^~
               operator==
/in/ex6.cpp:104:16: error: 'class BinaryTree' has no member named 'operator<<'; did you mean 'operator=='?
  right.operator<<(&os, &tree);
                ^~
                operator==
/in/ex6.cpp:105:13: error: 'const class BinaryTree' has no member named 'val'
  os=os+tree.val+" ";
             ^~~
/in/ex6.cpp: At global scope:
/in/ex6.cpp:108:39: error: ISO C++ forbids declaration of 'copy' with no type [-fpermissive]
 BinaryTree::*copy(const TreeNode *root)
                                       ^
/in/ex6.cpp: In function 'int BinaryTree::* copy(const TreeNode*)':
/in/ex6.cpp:112:14: error: expected type-specifier before '*' token
   return new *BinaryTree();
              ^
/in/ex6.cpp:114:20: error: expected type-specifier before '*' token
  TreeNode *is= new *TreeNode();
                    ^
/in/ex6.cpp:116:26: error: cannot convert 'int BinaryTree::*' to 'TreeNode*' in assignment
  is->left=copy(root->left);
                          ^
/in/ex6.cpp:117:28: error: cannot convert 'int BinaryTree::*' to 'TreeNode*' in assignment
  is->right=copy(root->right);
                            ^
/in/ex6.cpp:118:10: error: cannot convert 'TreeNode' to 'int BinaryTree::*' in return
  return *is;
          ^~
/in/ex6.cpp: In function 'void removeAll(TreeNode*)':
/in/ex6.cpp:123:5: error: 'isEmpty' was not declared in this scope
  if(isEmpty()) return;
     ^~~~~~~
/in/ex6.cpp:127:10: error: type 'struct TreeNode' argument given to 'delete', expected pointer
  delete *root;
          ^~~~
/in/ex6.cpp: In member function 'bool BinaryTree::equal(TreeNode*, TreeNode*) const':
/in/ex6.cpp:133:10: error: no match for 'operator==' (operand types are 'TreeNode' and 'std::nullptr_t')
  if(*root==nullptr&&*other==nullptr) return true;
     ~~~~~^~~~~~~~~
In file included from /usr/include/c++/7/iosfwd:40:0,
                 from /usr/include/c++/7/ios:38,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/postypes.h:216:5: note: candidate: template<class _StateT> bool std::operator==(const std::fpos<_StateT>&, const std::fpos<_StateT>&)
     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
     ^~~~~~~~
/usr/include/c++/7/bits/postypes.h:216:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::fpos<_StateT>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:64:0,
                 from /usr/include/c++/7/bits/char_traits.h:39,
                 from /usr/include/c++/7/ios:40,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/stl_pair.h:448:5: note: candidate: template<class _T1, class _T2> constexpr bool std::operator==(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&)
     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
     ^~~~~~~~
/usr/include/c++/7/bits/stl_pair.h:448:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::pair<_T1, _T2>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:67:0,
                 from /usr/include/c++/7/bits/char_traits.h:39,
                 from /usr/include/c++/7/ios:40,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/stl_iterator.h:302:5: note: candidate: template<class _Iterator> constexpr bool std::operator==(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&)
     operator==(const reverse_iterator<_Iterator>& __x,
     ^~~~~~~~
/usr/include/c++/7/bits/stl_iterator.h:302:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::reverse_iterator<_Iterator>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:67:0,
                 from /usr/include/c++/7/bits/char_traits.h:39,
                 from /usr/include/c++/7/ios:40,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/stl_iterator.h:340:5: note: candidate: template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_IteratorR>&)
     operator==(const reverse_iterator<_IteratorL>& __x,
     ^~~~~~~~
/usr/include/c++/7/bits/stl_iterator.h:340:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::reverse_iterator<_Iterator>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:67:0,
                 from /usr/include/c++/7/bits/char_traits.h:39,
                 from /usr/include/c++/7/ios:40,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/stl_iterator.h:1121:5: note: candidate: template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const std::move_iterator<_IteratorL>&, const std::move_iterator<_IteratorR>&)
     operator==(const move_iterator<_IteratorL>& __x,
     ^~~~~~~~
/usr/include/c++/7/bits/stl_iterator.h:1121:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::move_iterator<_IteratorL>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:67:0,
                 from /usr/include/c++/7/bits/char_traits.h:39,
                 from /usr/include/c++/7/ios:40,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/stl_iterator.h:1127:5: note: candidate: template<class _Iterator> constexpr bool std::operator==(const std::move_iterator<_IteratorL>&, const std::move_iterator<_IteratorL>&)
     operator==(const move_iterator<_Iterator>& __x,
     ^~~~~~~~
/usr/include/c++/7/bits/stl_iterator.h:1127:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::move_iterator<_IteratorL>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/string:41:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/allocator.h:146:5: note: candidate: template<class _T1, class _T2> bool std::operator==(const std::allocator<_CharT>&, const std::allocator<_T2>&)
     operator==(const allocator<_T1>&, const allocator<_T2>&)
     ^~~~~~~~
/usr/include/c++/7/bits/allocator.h:146:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::allocator<_CharT>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/string:41:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/allocator.h:152:5: note: candidate: template<class _Tp> bool std::operator==(const std::allocator<_CharT>&, const std::allocator<_CharT>&)
     operator==(const allocator<_Tp>&, const allocator<_Tp>&)
     ^~~~~~~~
/usr/include/c++/7/bits/allocator.h:152:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::allocator<_CharT>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/basic_string.h:48:0,
                 from /usr/include/c++/7/string:52,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/string_view:450:5: note: candidate: template<class _CharT, class _Traits> constexpr bool std::operator==(std::basic_string_view<_CharT, _Traits>, std::basic_string_view<_CharT, _Traits>)
     operator==(basic_string_view<_CharT, _Traits> __x,
     ^~~~~~~~
/usr/include/c++/7/string_view:450:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'std::basic_string_view<_CharT, _Traits>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/basic_string.h:48:0,
                 from /usr/include/c++/7/string:52,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/string_view:456:5: note: candidate: template<class _CharT, class _Traits> constexpr bool std::operator==(std::basic_string_view<_CharT, _Traits>, std::__detail::__idt<std::basic_string_view<_CharT, _Traits> >)
     operator==(basic_string_view<_CharT, _Traits> __x,
     ^~~~~~~~
/usr/include/c++/7/string_view:456:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'std::basic_string_view<_CharT, _Traits>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/basic_string.h:48:0,
                 from /usr/include/c++/7/string:52,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/string_view:462:5: note: candidate: template<class _CharT, class _Traits> constexpr bool std::operator==(std::__detail::__idt<std::basic_string_view<_CharT, _Traits> >, std::basic_string_view<_CharT, _Traits>)
     operator==(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
     ^~~~~~~~
/usr/include/c++/7/string_view:462:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'std::nullptr_t'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/string:52:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/basic_string.h:6009:5: note: candidate: template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&)
     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
     ^~~~~~~~
/usr/include/c++/7/bits/basic_string.h:6009:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/string:52:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/basic_string.h:6017:5: note: candidate: template<class _CharT> typename __gnu_cxx::__enable_if<std::__is_char<_Tp>::__value, bool>::__type std::operator==(const std::__cxx11::basic_string<_CharT>&, const std::__cxx11::basic_string<_CharT>&)
     operator==(const basic_string<_CharT>& __lhs,
     ^~~~~~~~
/usr/include/c++/7/bits/basic_string.h:6017:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::__cxx11::basic_string<_CharT>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/string:52:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/basic_string.h:6031:5: note: candidate: template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const _CharT*, const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&)
     operator==(const _CharT* __lhs,
     ^~~~~~~~
/usr/include/c++/7/bits/basic_string.h:6031:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   mismatched types 'const _CharT*' and 'TreeNode'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/string:52:0,
                 from /usr/include/c++/7/bits/locale_classes.h:40,
                 from /usr/include/c++/7/bits/ios_base.h:41,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/basic_string.h:6043:5: note: candidate: template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, const _CharT*)
     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
     ^~~~~~~~
/usr/include/c++/7/bits/basic_string.h:6043:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
In file included from /usr/include/c++/7/bits/ios_base.h:46:0,
                 from /usr/include/c++/7/ios:42,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/system_error:292:3: note: candidate: bool std::operator==(const std::error_code&, const std::error_code&)
   operator==(const error_code& __lhs, const error_code& __rhs) noexcept
   ^~~~~~~~
/usr/include/c++/7/system_error:292:3: note:   no known conversion for argument 1 from 'TreeNode' to 'const std::error_code&'
/usr/include/c++/7/system_error:297:3: note: candidate: bool std::operator==(const std::error_code&, const std::error_condition&)
   operator==(const error_code& __lhs, const error_condition& __rhs) noexcept
   ^~~~~~~~
/usr/include/c++/7/system_error:297:3: note:   no known conversion for argument 1 from 'TreeNode' to 'const std::error_code&'
/usr/include/c++/7/system_error:304:3: note: candidate: bool std::operator==(const std::error_condition&, const std::error_code&)
   operator==(const error_condition& __lhs, const error_code& __rhs) noexcept
   ^~~~~~~~
/usr/include/c++/7/system_error:304:3: note:   no known conversion for argument 1 from 'TreeNode' to 'const std::error_condition&'
/usr/include/c++/7/system_error:311:3: note: candidate: bool std::operator==(const std::error_condition&, const std::error_condition&)
   operator==(const error_condition& __lhs,
   ^~~~~~~~
/usr/include/c++/7/system_error:311:3: note:   no known conversion for argument 1 from 'TreeNode' to 'const std::error_condition&'
In file included from /usr/include/c++/7/bits/locale_facets.h:48:0,
                 from /usr/include/c++/7/bits/basic_ios.h:37,
                 from /usr/include/c++/7/ios:44,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/streambuf_iterator.h:204:5: note: candidate: template<class _CharT, class _Traits> bool std::operator==(const std::istreambuf_iterator<_CharT, _Traits>&, const std::istreambuf_iterator<_CharT, _Traits>&)
     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
     ^~~~~~~~
/usr/include/c++/7/bits/streambuf_iterator.h:204:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:12: note:   'TreeNode' is not derived from 'const std::istreambuf_iterator<_CharT, _Traits>'
  if(*root==nullptr&&*other==nullptr) return true;
            ^~~~~~~
/in/ex6.cpp:133:27: error: no match for 'operator==' (operand types are 'TreeNode' and 'std::nullptr_t')
  if(*root==nullptr&&*other==nullptr) return true;
                     ~~~~~~^~~~~~~~~
In file included from /usr/include/c++/7/iosfwd:40:0,
                 from /usr/include/c++/7/ios:38,
                 from /usr/include/c++/7/ostream:38,
                 from /usr/include/c++/7/iostream:39,
                 from /in/ex6.cpp:1:
/usr/include/c++/7/bits/postypes.h:216:5: note: candidate: template<class _StateT> bool std::operator==(const std::fpos<_StateT>&, const std::fpos<_StateT>&)
     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
     ^~~~~~~~
/usr/include/c++/7/bits/postypes.h:216:5: note:   template argument deduction/substitution failed:
/in/ex6.cpp:133:29: note:   'TreeNode' is not derived from 'const std::fpos<_StateT>'
  if(*root==nullptr&&*other==nullptr) return true;
                             ^~~~~~~
In file included from /usr