Language: C++

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

int main() {
  int n,ooe,x;
  cin >> n;
  ooe = 0;
  vector<int> vec(n);
  for(int i = 0 ; i < n ; i++) {
    cin >> vec.at(i);
    if(vec.at(i) < 0){
      ooe++;
    }
  }
  
  sort(vec.begin(), vec.end());
  int count = 0 ;
  
  if(ooe%2 = 0){
    for(int i = 0 ; i < n ; i++) {
      if(vec.at(i) < 0){
        x += vec.at(i)*(-1);
      }
      else {
        x += vec.at(i);
      }
    }
    cout << x << endl;
  }
  else {
    for(int i = 0 ; i < n ; i++) {
      if(vec.at(i) < 0){
        x += vec.at(i)*(-1);
        count++;
      }
      else {
        x += vec.at(i);
      }
    }
    cout << x - vec.at(count)*2 << endl;
  }
}

Compiler output:
a.cc:2:1: error: 'usnig' does not name a type
    2 | usnig namespace std;
      | ^~~~~
a.cc: In function 'int main()':
a.cc:6:3: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    6 |   cin >> n;
      |   ^~~
      |   std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146,
                 from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:8:3: error: 'vector' was not declared in this scope
    8 |   vector<int> vec(n);
      |   ^~~~~~
a.cc:8:3: 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:
/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:8:10: error: expected primary-expression before 'int'
    8 |   vector<int> vec(n);
      |          ^~~
a.cc:10:12: error: 'vec' was not declared in this scope
   10 |     cin >> vec.at(i);
      |            ^~~
a.cc:16:8: error: 'vec' was not declared in this scope
   16 |   sort(vec.begin(), vec.end());
      |        ^~~
a.cc:16:3: error: 'sort' was not declared in this scope; did you mean 'std::sort'?
   16 |   sort(vec.begin(), vec.end());
      |   ^~~~
      |   std::sort
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:296:1: note: 'std::sort' declared here
  296 | sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
      | ^~~~
a.cc:19:9: error: lvalue required as left operand of assignment
   19 |   if(ooe%2 = 0){
      |      ~~~^~
a.cc:28:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   28 |     cout << x << 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:28:18: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   28 |     cout << x << 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)
      |     ^~~~
a.cc:40:5: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   40 |     cout << x - vec.at(count)*2 << 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:40:36: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   40 |     cout << x - vec.at(count)*2 << endl;
      |                                    ^~~~
      |                                    std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~