Language: C++

#include <bits/stdc++.h>
using namespace std;

struct Node{
Node *r, *l, *p;
int key;
};

Node *T;

void insert(int x){

Node *z;
z.p = z.r = z.l = NIL;
z.p = k;
Node *y = NIL;
Node *x = T;

while(x != NIL){
y = x;
if(z->key < x->key){
x = x.l;
}else if(z -> key > x -> key){
x = x.r;
}
}

z.p = y;
if(y == NIL){
z = T;
}else if(y -> key < z -> key){
y.r = z;
}else if(y -> key < z -> key){
y.r = z;
}




}

void pre_print(Node x){
  if(x == -1) return;
  cout << " " << x;
  pre_print(T.l);
  pre_print(T.r);
}
 
void in_print(Node x){
  if(x == -1) return;
  in_print(T.l);
  cout << " " << x;
  in_print(T.r);
}



int main(){

int n;
string str;

cin >> n;

for(int i = 0; i < n; i++){
int k;
cin >> str >> k;
if(str == "insert"){
insert(k);
}else if(str == "print"){
in_print(T);
cout << endl;
pre_print(T);
cout << endl;
}
}



}

Compiler output:
a.cc: In function 'void insert(int)':
a.cc:14:3: error: request for member 'p' in 'z', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   14 | z.p = z.r = z.l = NIL;
      |   ^
a.cc:14:9: error: request for member 'r' in 'z', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   14 | z.p = z.r = z.l = NIL;
      |         ^
a.cc:14:15: error: request for member 'l' in 'z', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   14 | z.p = z.r = z.l = NIL;
      |               ^
a.cc:14:19: error: 'NIL' was not declared in this scope
   14 | z.p = z.r = z.l = NIL;
      |                   ^~~
a.cc:15:3: error: request for member 'p' in 'z', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   15 | z.p = k;
      |   ^
a.cc:15:7: error: 'k' was not declared in this scope
   15 | z.p = k;
      |       ^
a.cc:17:7: error: declaration of 'Node* x' shadows a parameter
   17 | Node *x = T;
      |       ^
a.cc:11:17: note: 'int x' previously declared here
   11 | void insert(int x){
      |             ~~~~^
a.cc:22:7: error: request for member 'l' in 'x', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   22 | x = x.l;
      |       ^
a.cc:24:7: error: request for member 'r' in 'x', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   24 | x = x.r;
      |       ^
a.cc:28:3: error: request for member 'p' in 'z', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   28 | z.p = y;
      |   ^
a.cc:32:3: error: request for member 'r' in 'y', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   32 | y.r = z;
      |   ^
a.cc:34:3: error: request for member 'r' in 'y', which is of pointer type 'Node*' (maybe you meant to use '->' ?)
   34 | y.r = z;
      |   ^
a.cc: In function 'void pre_print(Node)':
a.cc:43:8: error: no match for 'operator==' (operand types are 'Node' and 'int')
   43 |   if(x == -1) return;
      |      ~ ^~ ~~
      |      |    |
      |      Node int
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181,
                 from a.cc:1:
/usr/include/c++/14/bits/regex.h:1103:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1103 |     operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1103:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/regex.h:1199:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)'
 1199 |     operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1199:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/regex.h:1274:5: note: candidate: 'template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator==(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)'
 1274 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1274:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/regex.h:1366:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1366 |     operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1366:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/regex.h:1441:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1441 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1441:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/regex.h:1534:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1534 |     operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1534:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   mismatched types 'const std::__cxx11::sub_match<_BiIter>' and 'int'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/regex.h:1613:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator==(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1613 |     operator==(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1613:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/regex.h:2186:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator==(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2186 |     operator==(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2186:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
   43 |   if(x == -1) return;
      |            ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/bits/stl_pair.h:1033:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator==(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1033 |     operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1033:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::pair<_T1, _T2>'
   43 |   if(x == -1) return;
      |            ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67:
/usr/include/c++/14/bits/stl_iterator.h:441:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  441 |     operator==(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:441:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::reverse_iterator<_Iterator>'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/stl_iterator.h:486:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  486 |     operator==(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:486:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::reverse_iterator<_Iterator>'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1667 |     operator==(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1667:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::move_iterator<_IteratorL>'
   43 |   if(x == -1) return;
      |            ^
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator==(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1737 |     operator==(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1737:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::move_iterator<_IteratorL>'
   43 |   if(x == -1) return;
      |            ^
In file included from /usr/include/c++/14/bits/char_traits.h:42,
                 from /usr/include/c++/14/string:42,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/postypes.h:192:5: note: candidate: 'template<class _StateT> bool std::operator==(const fpos<_StateT>&, const fpos<_StateT>&)'
  192 |     operator==(const fpos<_StateT>& __lhs, const fpos<_StateT>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/postypes.h:192:5: note:   template argument deduction/substitution failed:
a.cc:43:12: note:   'Node' is not derived from 'const std::fpos<_StateT>'
   43 |   if(x == -1) return;
      |            ^
In file included from /usr/include/c++/14/string:43:
/usr/include/c++/14/bits/allocator.h:235:5: note: candidate: 'template<class _T1, class _