Language: C++

#include<iostream>
using namespace std;
int main(){
????int a;
????int b;
????cin >> a >>?? b;
????if(a < b){
????????cout << a << " < " << b << endl;
????}
????if(a == b){
????????cout << a << " == " << b << endl;
????}
????if(a > b){
????????cout << a << " > " << b << endl;
????}
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:1: error: expected primary-expression before '?' token
    4 | ????int a;
      | ^
a.cc:4:2: error: expected primary-expression before '?' token
    4 | ????int a;
      |  ^
a.cc:4:3: error: expected primary-expression before '?' token
    4 | ????int a;
      |   ^
a.cc:4:4: error: expected primary-expression before '?' token
    4 | ????int a;
      |    ^
a.cc:4:5: error: expected primary-expression before 'int'
    4 | ????int a;
      |     ^~~
a.cc:4:5: error: expected ':' before 'int'
    4 | ????int a;
      |     ^~~
      |     :
a.cc:4:5: error: expected primary-expression before 'int'
    4 | ????int a;
      |     ^~~
a.cc:4:5: error: expected ':' before 'int'
    4 | ????int a;
      |     ^~~
      |     :
a.cc:4:5: error: expected primary-expression before 'int'
    4 | ????int a;
      |     ^~~
a.cc:4:5: error: expected ':' before 'int'
    4 | ????int a;
      |     ^~~
      |     :
a.cc:4:5: error: expected primary-expression before 'int'
    4 | ????int a;
      |     ^~~
a.cc:4:5: error: expected ':' before 'int'
    4 | ????int a;
      |     ^~~
      |     :
a.cc:4:5: error: expected primary-expression before 'int'
    4 | ????int a;
      |     ^~~
a.cc:5:1: error: expected primary-expression before '?' token
    5 | ????int b;
      | ^
a.cc:5:2: error: expected primary-expression before '?' token
    5 | ????int b;
      |  ^
a.cc:5:3: error: expected primary-expression before '?' token
    5 | ????int b;
      |   ^
a.cc:5:4: error: expected primary-expression before '?' token
    5 | ????int b;
      |    ^
a.cc:5:5: error: expected primary-expression before 'int'
    5 | ????int b;
      |     ^~~
a.cc:5:5: error: expected ':' before 'int'
    5 | ????int b;
      |     ^~~
      |     :
a.cc:5:5: error: expected primary-expression before 'int'
    5 | ????int b;
      |     ^~~
a.cc:5:5: error: expected ':' before 'int'
    5 | ????int b;
      |     ^~~
      |     :
a.cc:5:5: error: expected primary-expression before 'int'
    5 | ????int b;
      |     ^~~
a.cc:5:5: error: expected ':' before 'int'
    5 | ????int b;
      |     ^~~
      |     :
a.cc:5:5: error: expected primary-expression before 'int'
    5 | ????int b;
      |     ^~~
a.cc:5:5: error: expected ':' before 'int'
    5 | ????int b;
      |     ^~~
      |     :
a.cc:5:5: error: expected primary-expression before 'int'
    5 | ????int b;
      |     ^~~
a.cc:6:1: error: expected primary-expression before '?' token
    6 | ????cin >> a >>?? b;
      | ^
a.cc:6:2: error: expected primary-expression before '?' token
    6 | ????cin >> a >>?? b;
      |  ^
a.cc:6:3: error: expected primary-expression before '?' token
    6 | ????cin >> a >>?? b;
      |   ^
a.cc:6:4: error: expected primary-expression before '?' token
    6 | ????cin >> a >>?? b;
      |    ^
a.cc:6:12: error: 'a' was not declared in this scope
    6 | ????cin >> a >>?? b;
      |            ^
a.cc:6:16: error: expected primary-expression before '?' token
    6 | ????cin >> a >>?? b;
      |                ^
a.cc:6:17: error: expected primary-expression before '?' token
    6 | ????cin >> a >>?? b;
      |                 ^
a.cc:6:19: error: 'b' was not declared in this scope
    6 | ????cin >> a >>?? b;
      |                   ^
a.cc:6:20: error: expected ':' before ';' token
    6 | ????cin >> a >>?? b;
      |                    ^
      |                    :
a.cc:6:20: error: expected primary-expression before ';' token
a.cc:6:20: error: expected ':' before ';' token
    6 | ????cin >> a >>?? b;
      |                    ^
      |                    :
a.cc:6:20: error: expected primary-expression before ';' token
a.cc:6:20: error: expected ':' before ';' token
    6 | ????cin >> a >>?? b;
      |                    ^
      |                    :
a.cc:6:20: error: expected primary-expression before ';' token
a.cc:6:20: error: expected ':' before ';' token
    6 | ????cin >> a >>?? b;
      |                    ^
      |                    :
a.cc:6:20: error: expected primary-expression before ';' token
a.cc:6:20: error: expected ':' before ';' token
    6 | ????cin >> a >>?? b;
      |                    ^
      |                    :
a.cc:6:20: error: expected primary-expression before ';' token
a.cc:6:20: error: expected ':' before ';' token
    6 | ????cin >> a >>?? b;
      |                    ^
      |                    :
a.cc:6:20: error: expected primary-expression before ';' token
a.cc:7:1: error: expected primary-expression before '?' token
    7 | ????if(a < b){
      | ^
a.cc:7:2: error: expected primary-expression before '?' token
    7 | ????if(a < b){
      |  ^
a.cc:7:3: error: expected primary-expression before '?' token
    7 | ????if(a < b){
      |   ^
a.cc:7:4: error: expected primary-expression before '?' token
    7 | ????if(a < b){
      |    ^
a.cc:7:5: error: expected primary-expression before 'if'
    7 | ????if(a < b){
      |     ^~
a.cc:7:5: error: expected ':' before 'if'
    7 | ????if(a < b){
      |     ^~
      |     :
a.cc:7:5: error: expected primary-expression before 'if'
    7 | ????if(a < b){
      |     ^~
a.cc:7:5: error: expected ':' before 'if'
    7 | ????if(a < b){
      |     ^~
      |     :
a.cc:7:5: error: expected primary-expression before 'if'
    7 | ????if(a < b){
      |     ^~
a.cc:7:5: error: expected ':' before 'if'
    7 | ????if(a < b){
      |     ^~
      |     :
a.cc:7:5: error: expected primary-expression before 'if'
    7 | ????if(a < b){
      |     ^~
a.cc:7:5: error: expected ':' before 'if'
    7 | ????if(a < b){
      |     ^~
      |     :
a.cc:7:5: error: expected primary-expression before 'if'
    7 | ????if(a < b){
      |     ^~
a.cc:10:1: error: expected primary-expression before '?' token
   10 | ????if(a == b){
      | ^
a.cc:10:2: error: expected primary-expression before '?' token
   10 | ????if(a == b){
      |  ^
a.cc:10:3: error: expected primary-expression before '?' token
   10 | ????if(a == b){
      |   ^
a.cc:10:4: error: expected primary-expression before '?' token
   10 | ????if(a == b){
      |    ^
a.cc:10:5: error: expected primary-expression before 'if'
   10 | ????if(a == b){
      |     ^~
a.cc:10:5: error: expected ':' before 'if'
   10 | ????if(a == b){
      |     ^~
      |     :
a.cc:10:5: error: expected primary-expression before 'if'
   10 | ????if(a == b){
      |     ^~
a.cc:10:5: error: expected ':' before 'if'
   10 | ????if(a == b){
      |     ^~
      |     :
a.cc:10:5: error: expected primary-expression before 'if'
   10 | ????if(a == b){
      |     ^~
a.cc:10:5: error: expected ':' before 'if'
   10 | ????if(a == b){
      |     ^~
      |     :
a.cc:10:5: error: expected primary-expression before 'if'
   10 | ????if(a == b){
      |     ^~
a.cc:10:5: error: expected ':' before 'if'
   10 | ????if(a == b){
      |     ^~
      |     :
a.cc:10:5: error: expected primary-expression before 'if'
   10 | ????if(a == b){
      |     ^~
a.cc:13:1: error: expected primary-expression before '?' token
   13 | ????if(a > b){
      | ^
a.cc:13:2: error: expected primary-expression before '?' token
   13 | ????if(a > b){
      |  ^
a.cc:13:3: error: expected primary-expression before '?' token
   13 | ????if(a > b){
      |   ^
a.cc:13:4: error: expected primary-expression before '?' token
   13 | ????if(a > b){
      |    ^
a.cc:13:5: error: expected primary-expression before 'if'
   13 | ????if(a > b){
      |     ^~
a.cc:13:5: error: expected ':' before 'if'
   13 | ????if(a > b){
      |     ^~
      |     :
a.cc:13:5: error: expected primary-expression before 'if'
   13 | ????if(a > b){
      |     ^~
a.cc:13:5: error: expected ':' before 'if'
   13 | ????if(a > b){
      |     ^~
      |     :
a.cc:13:5: error: expected primary-expression before 'if'
   13 | ????if(a > b){
      |     ^~
a.cc:13:5: error: expected ':' before 'if'
   13 | ????if(a > b){
      |     ^~
      |     :
a.cc:13:5: error: expected primary-expression before 'if'
   13 | ????if(a > b){
      |     ^~
a.cc:13:5: error: expected ':' before 'if'
   13 | ????if(a > b){
      |     ^~
      |     :
a.cc:13:5: error: expected primary-expression before 'if'
   13 | ????if(a > b){
      |     ^~