Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
{
	string s;
	cin>>s;
	vector<char> q;
	int i,n,qu,qu2;
	char c;
	bool b=1;
	for(i=0;i<s.size();++i)
		q.push_back(s[i]);
	cin>>n;
	while(n--)
	{
		cin>>qu;
		if(qu==1)
			b=!b;
		else
		{
			cin>>qu2;
			cin>>c;
			if(qu2==1)
				q.push_front(c);
			else
				q.push_back(c);
		}
	}
	
	vector<int>::iterator it;
	if(b)
	{
		for(it=q.begin();it!=q.end();it++)
			cout<<*it;
		cout<<endl;
	}
	else
	{
		for(it=q.end();it!=q.begin();it++)
			cout<<*it;
		cout<<endl;
	}
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:24:35: error: 'class std::vector<char>' has no member named 'push_front'
   24 |                                 q.push_front(c);
      |                                   ^~~~~~~~~~
a.cc:33:32: error: no match for 'operator=' (operand types are 'std::vector<int>::iterator' and 'std::vector<char>::iterator')
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:67,
                 from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_iterator.h:1038:11: note: candidate: 'constexpr __gnu_cxx::__normal_iterator<int*, std::vector<int> >& __gnu_cxx::__normal_iterator<int*, std::vector<int> >::operator=(const __gnu_cxx::__normal_iterator<int*, std::vector<int> >&)'
 1038 |     class __normal_iterator
      |           ^~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1038:11: note:   no known conversion for argument 1 from 'std::vector<char>::iterator' to 'const __gnu_cxx::__normal_iterator<int*, std::vector<int> >&'
/usr/include/c++/14/bits/stl_iterator.h:1038:11: note: candidate: 'constexpr __gnu_cxx::__normal_iterator<int*, std::vector<int> >& __gnu_cxx::__normal_iterator<int*, std::vector<int> >::operator=(__gnu_cxx::__normal_iterator<int*, std::vector<int> >&&)'
/usr/include/c++/14/bits/stl_iterator.h:1038:11: note:   no known conversion for argument 1 from 'std::vector<char>::iterator' to '__gnu_cxx::__normal_iterator<int*, std::vector<int> >&&'
a.cc:33:36: error: no match for 'operator!=' (operand types are 'std::vector<int>::iterator' and 'std::vector<char>::iterator')
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                  ~~^~~~~~~~~
      |                                  |        |
      |                                  |        __normal_iterator<char*,vector<char>>
      |                                  __normal_iterator<int*,vector<int>>
In file included from /usr/include/c++/14/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:181:
/usr/include/c++/14/bits/regex.h:1132:5: note: candidate: 'template<class _BiIter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const sub_match<_BiIter>&)'
 1132 |     operator!=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1132:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/regex.h:1212:5: 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>&)'
 1212 |     operator!=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1212:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/regex.h:1305:5: 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>&)'
 1305 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1305:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/regex.h:1379:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)'
 1379 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1379:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<char>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/regex.h:1473:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)'
 1473 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1473:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/regex.h:1547:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)'
 1547 |     operator!=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1547:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<char>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/regex.h:1647:5: note: candidate: 'template<class _Bi_iter> bool std::__cxx11::operator!=(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)'
 1647 |     operator!=(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:1647:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::sub_match<_BiIter>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/regex.h:2213:5: note: candidate: 'template<class _Bi_iter, class _Alloc> bool std::__cxx11::operator!=(const match_results<_BiIter, _Alloc>&, const match_results<_BiIter, _Alloc>&)'
 2213 |     operator!=(const match_results<_Bi_iter, _Alloc>& __m1,
      |     ^~~~~~~~
/usr/include/c++/14/bits/regex.h:2213:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::__cxx11::match_results<_BiIter, _Alloc>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64:
/usr/include/c++/14/bits/stl_pair.h:1052:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator!=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1052 |     operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1052:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::pair<_T1, _T2>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/stl_iterator.h:455:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  455 |     operator!=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:455:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::reverse_iterator<_Iterator>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/stl_iterator.h:500:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  500 |     operator!=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:500:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::reverse_iterator<_Iterator>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1686 |     operator!=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1686:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::move_iterator<_IteratorL>'
   33 |                 for(it=q.begin();it!=q.end();it++)
      |                                            ^
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator!=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1753 |     operator!=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1753:5: note:   template argument deduction/substitution failed:
a.cc:33:44: note:   'std::vector<int>::iterator' is not derived from 'const std::move_iterator<_IteratorL>'
   33 |                 for(it=q.begin();it