Language: C++

#include <iostream>

int main () 
{
int a;
int b;

cin >> a;
cin >> b;

if (a < b) {
cout << ???a < b??? << endl;
} else if (a == b) {
cout << ??? a == b??? << endl;
} else if (a > b) {
cout << ??? a > b ??? << endl;
}

return 0;

}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:1: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    8 | cin >> a;
      | ^~~
      | 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:12:1: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   12 | 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:12:9: error: expected primary-expression before '?' token
   12 | cout << ???a < b??? << endl;
      |         ^
a.cc:12:10: error: expected primary-expression before '?' token
   12 | cout << ???a < b??? << endl;
      |          ^
a.cc:12:11: error: expected primary-expression before '?' token
   12 | cout << ???a < b??? << endl;
      |           ^
a.cc:12:18: error: expected primary-expression before '?' token
   12 | cout << ???a < b??? << endl;
      |                  ^
a.cc:12:19: error: expected primary-expression before '?' token
   12 | cout << ???a < b??? << endl;
      |                   ^
a.cc:12:21: error: expected primary-expression before '<<' token
   12 | cout << ???a < b??? << endl;
      |                     ^~
a.cc:12:24: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   12 | 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:12:28: error: expected ':' before ';' token
   12 | cout << ???a < b??? << endl;
      |                            ^
      |                            :
a.cc:12:28: error: expected primary-expression before ';' token
a.cc:12:28: error: expected ':' before ';' token
   12 | cout << ???a < b??? << endl;
      |                            ^
      |                            :
a.cc:12:28: error: expected primary-expression before ';' token
a.cc:12:28: error: expected ':' before ';' token
   12 | cout << ???a < b??? << endl;
      |                            ^
      |                            :
a.cc:12:28: error: expected primary-expression before ';' token
a.cc:12:28: error: expected ':' before ';' token
   12 | cout << ???a < b??? << endl;
      |                            ^
      |                            :
a.cc:12:28: error: expected primary-expression before ';' token
a.cc:12:28: error: expected ':' before ';' token
   12 | cout << ???a < b??? << endl;
      |                            ^
      |                            :
a.cc:12:28: error: expected primary-expression before ';' token
a.cc:12:28: error: expected ':' before ';' token
   12 | cout << ???a < b??? << endl;
      |                            ^
      |                            :
a.cc:12:28: error: expected primary-expression before ';' token
a.cc:14:1: 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:14:9: error: expected primary-expression before '?' token
   14 | cout << ??? a == b??? << endl;
      |         ^
a.cc:14:10: error: expected primary-expression before '?' token
   14 | cout << ??? a == b??? << endl;
      |          ^
a.cc:14:11: error: expected primary-expression before '?' token
   14 | cout << ??? a == b??? << endl;
      |           ^
a.cc:14:20: error: expected primary-expression before '?' token
   14 | cout << ??? a == b??? << endl;
      |                    ^
a.cc:14:21: error: expected primary-expression before '?' token
   14 | cout << ??? a == b??? << endl;
      |                     ^
a.cc:14:23: error: expected primary-expression before '<<' token
   14 | cout << ??? a == b??? << endl;
      |                       ^~
a.cc:14:26: 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:14:30: error: expected ':' before ';' token
   14 | cout << ??? a == b??? << endl;
      |                              ^
      |                              :
a.cc:14:30: error: expected primary-expression before ';' token
a.cc:14:30: error: expected ':' before ';' token
   14 | cout << ??? a == b??? << endl;
      |                              ^
      |                              :
a.cc:14:30: error: expected primary-expression before ';' token
a.cc:14:30: error: expected ':' before ';' token
   14 | cout << ??? a == b??? << endl;
      |                              ^
      |                              :
a.cc:14:30: error: expected primary-expression before ';' token
a.cc:14:30: error: expected ':' before ';' token
   14 | cout << ??? a == b??? << endl;
      |                              ^
      |                              :
a.cc:14:30: error: expected primary-expression before ';' token
a.cc:14:30: error: expected ':' before ';' token
   14 | cout << ??? a == b??? << endl;
      |                              ^
      |                              :
a.cc:14:30: error: expected primary-expression before ';' token
a.cc:14:30: error: expected ':' before ';' token
   14 | cout << ??? a == b??? << endl;
      |                              ^
      |                              :
a.cc:14:30: error: expected primary-expression before ';' token
a.cc:16:1: 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:16:9: error: expected primary-expression before '?' token
   16 | cout << ??? a > b ??? << endl;
      |         ^
a.cc:16:10: error: expected primary-expression before '?' token
   16 | cout << ??? a > b ??? << endl;
      |          ^
a.cc:16:11: error: expected primary-expression before '?' token
   16 | cout << ??? a > b ??? << endl;
      |           ^
a.cc:16:20: error: expected primary-expression before '?' token
   16 | cout << ??? a > b ??? << endl;
      |                    ^
a.cc:16:21: error: expected primary-expression before '?' token
   16 | cout << ??? a > b ??? << endl;
      |                     ^
a.cc:16:23: error: expected primary-expression before '<<' token
   16 | cout << ??? a > b ??? << endl;
      |                       ^~
a.cc:16:26: 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)
      |     ^~~~
a.cc:16:30: error: expected ':' before ';' token
   16 | cout << ??? a > b ??? << endl;
      |                              ^
      |                              :
a.cc:16:30: error: expected primary-expression before ';' token
a.cc:16:30: error: expected ':' before ';' token
   16 | cout << ??? a > b ??? << endl;
      |                              ^
      |                              :
a.cc:16:30: error: expected primary-expression before ';' token
a.cc:16:30: error: expected ':' before ';' token
   16 | cout << ??? a > b ??? << endl;
      |                              ^
      |                              :
a.cc:16:30: error: expected primary-expression before ';' token
a.cc:16:30: error: expected ':' before ';' token
   16 | cout << ??? a > b ??? << endl;
      |                              ^
      |                              :
a.cc:16:30: error: expected primary-expression before ';' token
a.cc:16:30: error: expected ':' before ';' token
   16 | cout << ??? a > b ??? << endl;
      |                              ^
      |                              :
a.cc:16:30: error: expected primary-expression before ';' token
a.cc:16:30: error: expected ':' before ';' token
   16 | cout << ??? a > b ??? << endl;
      |                              ^
      |                              :
a.cc:16:30: error: expected primary-expression before ';' token