Language: C++

#include <iostream>
#include <stdio.h>

using namespace std;

int main()
{
	
	int x, y, z, op;

	while (1){
		cin >> x >> op >> y;

		if (op == '?'){ break; 
????????????????????????}
		
		if (op == '+'){
			z = x + y;
			cout << z << endl;
		}
		if (op == '-'){
			z = x - y;
			cout << z << endl;
		}
		if (op == '*'){
			z = x * y;
			cout << z << endl;
		}
		if (op == '/'){
			z = x / y;
			cout << z << endl;
		}
		
	}



	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:15:1: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      | ^
a.cc:15:2: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |  ^
a.cc:15:3: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |   ^
a.cc:15:4: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |    ^
a.cc:15:5: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |     ^
a.cc:15:6: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |      ^
a.cc:15:7: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |       ^
a.cc:15:8: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |        ^
a.cc:15:9: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |         ^
a.cc:15:10: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |          ^
a.cc:15:11: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |           ^
a.cc:15:12: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |            ^
a.cc:15:13: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |             ^
a.cc:15:14: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |              ^
a.cc:15:15: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |               ^
a.cc:15:16: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                ^
a.cc:15:17: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                 ^
a.cc:15:18: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                  ^
a.cc:15:19: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                   ^
a.cc:15:20: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                    ^
a.cc:15:21: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                     ^
a.cc:15:22: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                      ^
a.cc:15:23: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                       ^
a.cc:15:24: error: expected primary-expression before '?' token
   15 | ????????????????????????}
      |                        ^
a.cc:15:25: error: expected primary-expression before '}' token
   15 | ????????????????????????}
      |                         ^
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token
a.cc:15:25: error: expected ':' before '}' token
   15 | ????????????????????????}
      |                         ^
      |                         :
a.cc:15:25: error: expected primary-expression before '}' token