Language: C++

#include<bits/stdc++.h>
int main(void){
    int a_arr[3]={1,2,3},A,B;
    vector<int> v(a_arr,end(a_arr));
    cin>>A;
    cin>>B;
    auto rema = remove_if(v.begin(),v.end(),[&](int value){return value==A;});
    auto remb = remove_if(v.begin(),v.end(),[&](int value){return value==B;});
    v.erase(rema,v.end());
    v.erase(remb,v.end());
    cout<<v[0]<<endl;
    return 0;
    }

Compiler output:
a.cc: In function 'int main()':
a.cc:4:5: error: 'vector' was not declared in this scope
    4 |     vector<int> v(a_arr,end(a_arr));
      |     ^~~~~~
a.cc:4:5: note: suggested alternatives:
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_vector.h:428:11: note:   'std::vector'
  428 |     class vector : protected _Vector_base<_Tp, _Alloc>
      |           ^~~~~~
/usr/include/c++/14/vector:93:13: note:   'std::pmr::vector'
   93 |       using vector = std::vector<_Tp, polymorphic_allocator<_Tp>>;
      |             ^~~~~~
a.cc:4:12: error: expected primary-expression before 'int'
    4 |     vector<int> v(a_arr,end(a_arr));
      |            ^~~
a.cc:5:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |     cin>>A;
      |     ^~~
      |     std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:7:27: error: 'v' was not declared in this scope
    7 |     auto rema = remove_if(v.begin(),v.end(),[&](int value){return value==A;});
      |                           ^
a.cc:7:17: error: 'remove_if' was not declared in this scope; did you mean 'std::remove_if'?
    7 |     auto rema = remove_if(v.begin(),v.end(),[&](int value){return value==A;});
      |                 ^~~~~~~~~
      |                 std::remove_if
In file included from /usr/include/c++/14/algorithm:86,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:220:1: note: 'std::remove_if' declared here
  220 | remove_if(_ExecutionPolicy&& __exec, _ForwardIterator __first, _ForwardIterator __last, _UnaryPredicate __pred);
      | ^~~~~~~~~
a.cc:11:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   11 |     cout<<v[0]<<endl;
      |     ^~~~
      |     std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
a.cc:11:17: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   11 |     cout<<v[0]<<endl;
      |                 ^~~~
      |                 std::endl
In file included from /usr/include/c++/14/istream:41,
                 from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~