Language: C++

#include<bits/stdc++.h>
int main () {
  int N, T, A;
  vector<float> data(N,0);
  cin >> N;
  cin >> T >> A;
  for (int i = 0; i < N; i++) {
    int n;
    cin >> n;
    data.at(i) = T - n * 0.006;
  }
  int ans, num, keep =2000000000;
  for (int i = 0; i < N; i++) {
    num = A - data.at(i);
    if (keep > abs(num)) {
      keep = abs(num);
      num = i + 1;
    }
  }
  cout << num << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:3: error: 'vector' was not declared in this scope
    4 |   vector<float> data(N,0);
      |   ^~~~~~
a.cc:4:3: 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:4:10: error: expected primary-expression before 'float'
    4 |   vector<float> data(N,0);
      |          ^~~~~
a.cc:5:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    5 |   cin >> N;
      |   ^~~
      |   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:10:5: error: 'data' was not declared in this scope; did you mean 'std::data'?
   10 |     data.at(i) = T - n * 0.006;
      |     ^~~~
      |     std::data
In file included from /usr/include/c++/14/string:53,
                 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/range_access.h:344:5: note: 'std::data' declared here
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
a.cc:14:15: error: 'data' was not declared in this scope; did you mean 'std::data'?
   14 |     num = A - data.at(i);
      |               ^~~~
      |               std::data
/usr/include/c++/14/bits/range_access.h:344:5: note: 'std::data' declared here
  344 |     data(initializer_list<_Tp> __il) noexcept
      |     ^~~~
a.cc:20:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   20 |   cout << num << 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:20:18: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   20 |   cout << num << 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)
      |     ^~~~