Language: C++

#include <iostream>
using namespace std;

int main () 
{
int a,b;
cin >> a >> b;

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

return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:20: error: expected primary-expression before '?' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                    ^
a.cc:9:21: error: expected primary-expression before '?' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                     ^
a.cc:9:22: error: expected primary-expression before '?' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                      ^
a.cc:9:29: error: expected primary-expression before '?' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                             ^
a.cc:9:30: error: expected primary-expression before '?' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                              ^
a.cc:9:32: error: expected primary-expression before '<<' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                                ^~
a.cc:9:39: error: expected ':' before ';' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                                       ^
      |                                       :
a.cc:9:39: error: expected primary-expression before ';' token
a.cc:9:39: error: expected ':' before ';' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                                       ^
      |                                       :
a.cc:9:39: error: expected primary-expression before ';' token
a.cc:9:39: error: expected ':' before ';' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                                       ^
      |                                       :
a.cc:9:39: error: expected primary-expression before ';' token
a.cc:9:39: error: expected ':' before ';' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                                       ^
      |                                       :
a.cc:9:39: error: expected primary-expression before ';' token
a.cc:9:39: error: expected ':' before ';' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                                       ^
      |                                       :
a.cc:9:39: error: expected primary-expression before ';' token
a.cc:9:39: error: expected ':' before ';' token
    9 | if (a < b) cout << ???a < b??? << endl;
      |                                       ^
      |                                       :
a.cc:9:39: error: expected primary-expression before ';' token
a.cc:10:26: error: expected primary-expression before '?' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                          ^
a.cc:10:27: error: expected primary-expression before '?' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                           ^
a.cc:10:28: error: expected primary-expression before '?' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                            ^
a.cc:10:36: error: expected primary-expression before '?' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                    ^
a.cc:10:37: error: expected primary-expression before '?' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                     ^
a.cc:10:39: error: expected primary-expression before '<<' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                       ^~
a.cc:10:46: error: expected ':' before ';' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                              ^
      |                                              :
a.cc:10:46: error: expected primary-expression before ';' token
a.cc:10:46: error: expected ':' before ';' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                              ^
      |                                              :
a.cc:10:46: error: expected primary-expression before ';' token
a.cc:10:46: error: expected ':' before ';' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                              ^
      |                                              :
a.cc:10:46: error: expected primary-expression before ';' token
a.cc:10:46: error: expected ':' before ';' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                              ^
      |                                              :
a.cc:10:46: error: expected primary-expression before ';' token
a.cc:10:46: error: expected ':' before ';' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                              ^
      |                                              :
a.cc:10:46: error: expected primary-expression before ';' token
a.cc:10:46: error: expected ':' before ';' token
   10 | else if (a == b) cout << ???a == b??? << endl;
      |                                              ^
      |                                              :
a.cc:10:46: error: expected primary-expression before ';' token
a.cc:11:13: error: expected ';' before 'cout'
   11 | else (a > b) cout << ???a > b??? << endl;
      |             ^~~~~
      |             ;