Language: C++

#include <iostream>

int main(void){
    int A, B; cin >> A >> B;

    if(A+B>=A-B){
        if(A+B>=A*B){
            cout << A+B << endl;
        } else {
            cout << A*B << endl;
        }
    } else{
        if(A-B>=A*B){
            cout << A-B << endl;
        } else{
            cout << A*B << endl;
        }
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:15: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    4 |     int A, B; cin >> A >> B;
      |               ^~~
      |               std::cin
In file included 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:8:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    8 |             cout << A+B << 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:8:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
    8 |             cout << A+B << endl;
      |                            ^~~~
      |                            std::endl
In file included from /usr/include/c++/14/iostream:41:
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:10:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   10 |             cout << A*B << 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:10:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   10 |             cout << A*B << endl;
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:14:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   14 |             cout << A-B << 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:14:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   14 |             cout << A-B << endl;
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:16:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   16 |             cout << A*B << 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:16:28: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   16 |             cout << A*B << endl;
      |                            ^~~~
      |                            std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~