Language: C++

#include<iostream>
using namespace std;
int main()
{????????????int a, b;
	cin >> a >> b;
	if (a < b) { cout << "a<b"; }
	else if (a>b) { cout << "a>b "; }
	else { cout << "a==b" << endl; }
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:2: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |  ^
a.cc:4:3: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |   ^
a.cc:4:4: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |    ^
a.cc:4:5: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |     ^
a.cc:4:6: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |      ^
a.cc:4:7: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |       ^
a.cc:4:8: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |        ^
a.cc:4:9: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |         ^
a.cc:4:10: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |          ^
a.cc:4:11: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |           ^
a.cc:4:12: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |            ^
a.cc:4:13: error: expected primary-expression before '?' token
    4 | {????????????int a, b;
      |             ^
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:4:14: error: expected ':' before 'int'
    4 | {????????????int a, b;
      |              ^~~
      |              :
a.cc:4:14: error: expected primary-expression before 'int'
    4 | {????????????int a, b;
      |              ^~~
a.cc:5:16: error: 'a' was not declared in this scope
    5 |         cin >> a >> b;
      |                ^
a.cc:5:21: error: 'b' was not declared in this scope
    5 |         cin >> a >> b;
      |                     ^