Language: C++

#include <cstdio>
#include <cstdlib>
#include <string>
#include <iostream>
using namespace std;

struct Node {
	int key;
	Node *right, *left, *parent;
};

Node *root, *NIL;

void insert(int k) {
	Node *y = NIL;
	Node *x = root;
	Node *z;
	
	z = (Node *)malloc(sizeof(Node));
	z->key   = k;
	z->left  = NIL;
	z->right = NIL;
	
	while(x != NIL) {
		y = x;
		if(z->key < x->key) {
			x = x->left;
		} else {
			x = x->right;
		}
	}
	
	z->parent = y;
	if(y == NIL) {
		root = z;
	} else {
		if( z->key < y->key) {
			y->left = z;
		} else {
			y->right = z;
		}
	}
}

Node *find(Node *u,int k)
{
	while(u!=NIL&&k!=u->key)
	{
		if(k<u->key)u=u->left;
		else u=u->right;
	}
return u;
}

void inorder(Node *u) {
	if(u == NIL) return;
	inorder(u->left);
	printf(" %d",u->key);
	inorder(u->right);
}
void preorder(Node *u) {
	if(u == NIL) return;
	printf(" %d",u->key);
	preorder(u->left);
	preorder(u->right);
}
	
int main(void) {
	int n, i, x;
	string com;
	scanf("%d",&n);
	
	for(i=0;i<n;i++) {
		cin >> com;
		if(com=[0]=='f')
		{
			scanf("%d",&x);
			Node *t=find(root,x);
			if(t!=NIL)printf("yes\n");
			else printf("no\n");
		}
		if(com == "insert") {
			scanf("%d",&x);
			insert(x);
		} else if(com == "print") {
			inorder(root);
			printf("\n");
			preorder(root);
			printf("\n");
		}
	}

	return 0;
}



Compiler output:
a.cc: In function 'int main()':
a.cc:75:25: error: expected identifier before numeric constant
   75 |                 if(com=[0]=='f')
      |                         ^
a.cc: In lambda function:
a.cc:75:27: error: expected '{' before '==' token
   75 |                 if(com=[0]=='f')
      |                           ^~
a.cc: In function 'int main()':
a.cc:75:27: error: no match for 'operator==' (operand types are 'main()::<lambda()>' and 'char')
   75 |                 if(com=[0]=='f')
      |                        ~~~^~~~~
      |                        |    |
      |                        |    char
      |                        main()::<lambda()>
In file included from /usr/include/c++/14/bits/char_traits.h:42,
                 from /usr/include/c++/14/string:42,
                 from a.cc:3:
/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:75:29: note:   'main()::<lambda()>' is not derived from 'const std::fpos<_StateT>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
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 _T2> bool std::operator==(const allocator<_CharT>&, const allocator<_T2>&)'
  235 |     operator==(const allocator<_T1>&, const allocator<_T2>&)
      |     ^~~~~~~~
/usr/include/c++/14/bits/allocator.h:235:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   'main()::<lambda()>' is not derived from 'const std::allocator<_CharT>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
In file included from /usr/include/c++/14/string:48:
/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:75:29: note:   'main()::<lambda()>' is not derived from 'const std::reverse_iterator<_Iterator>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
/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:75:29: note:   'main()::<lambda()>' is not derived from 'const std::reverse_iterator<_Iterator>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
/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:75:29: note:   'main()::<lambda()>' is not derived from 'const std::move_iterator<_IteratorL>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
/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:75:29: note:   'main()::<lambda()>' is not derived from 'const std::move_iterator<_IteratorL>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/string: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:75:29: note:   'main()::<lambda()>' is not derived from 'const std::pair<_T1, _T2>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:629:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  629 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:629:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   'main()::<lambda()>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
/usr/include/c++/14/string_view:637:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  637 |     operator==(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:637:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   'main()::<lambda()>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
/usr/include/c++/14/string_view:644:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator==(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  644 |     operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:644:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'char'
   75 |                 if(com=[0]=='f')
      |                             ^~~
/usr/include/c++/14/bits/basic_string.h:3755:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3755 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3755:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   'main()::<lambda()>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
/usr/include/c++/14/bits/basic_string.h:3772:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3772 |     operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3772:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   'main()::<lambda()>' is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
/usr/include/c++/14/bits/basic_string.h:3819:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator==(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3819 |     operator==(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3819:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   mismatched types 'const _CharT*' and 'main()::<lambda()>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/tuple:2558:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator==(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2558 |     operator==(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2558:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   'main()::<lambda()>' is not derived from 'const std::tuple<_UTypes ...>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
In file included from /usr/include/c++/14/bits/locale_facets.h:48,
                 from /usr/include/c++/14/bits/basic_ios.h:37,
                 from /usr/include/c++/14/ios:46,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:4:
/usr/include/c++/14/bits/streambuf_iterator.h:234:5: note: candidate: 'template<class _CharT, class _Traits> bool std::operator==(const istreambuf_iterator<_CharT, _Traits>&, const istreambuf_iterator<_CharT, _Traits>&)'
  234 |     operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
      |     ^~~~~~~~
/usr/include/c++/14/bits/streambuf_iterator.h:234:5: note:   template argument deduction/substitution failed:
a.cc:75:29: note:   'main()::<lambda()>' is not derived from 'const std::istreambuf_iterator<_CharT, _Traits>'
   75 |                 if(com=[0]=='f')
      |                             ^~~
In file included from /usr/include/c++/14/bits/ios_