Language: C++

#include<iostream>
using namespace


int main(){

int x  , y;
char op;

while(1){
cin >> x >>  op  >> y;
if( op == "?" ) break;

if ( op == + ){ cout << x + y << endl};
if ( op == - ){ cout << x - y << endl};
if ( op == * ){ cout << x * y << endl};
if ( op == / ){ cout << x / y << endl}:

}

return 0 ;

}

Compiler output:
a.cc:5:1: error: expected identifier before 'int'
    5 | int main(){
      | ^~~
a.cc:2:16: error: expected ';' before 'int'
    2 | using namespace
      |                ^
      |                ;
......
    5 | int main(){
      | ~~~             
a.cc: In function 'int main()':
a.cc:11:1: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
   11 | cin >> x >>  op  >> y;
      | ^~~
      | 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:12:8: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   12 | if( op == "?" ) break;
      |     ~~~^~~~~~
a.cc:14:14: error: expected primary-expression before ')' token
   14 | if ( op == + ){ cout << x + y << endl};
      |              ^
a.cc:14:17: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   14 | if ( op == + ){ cout << x + y << 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:14:34: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   14 | if ( op == + ){ cout << x + y << 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:15:14: error: expected primary-expression before ')' token
   15 | if ( op == - ){ cout << x - y << endl};
      |              ^
a.cc:15:17: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   15 | if ( op == - ){ cout << x - y << 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:15:34: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   15 | if ( op == - ){ cout << x - y << endl};
      |                                  ^~~~
      |                                  std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:16:14: error: expected primary-expression before ')' token
   16 | if ( op == * ){ cout << x * y << endl};
      |              ^
a.cc:16:17: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   16 | if ( op == * ){ cout << x * y << 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:16:34: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   16 | if ( op == * ){ cout << x * y << endl};
      |                                  ^~~~
      |                                  std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:17:12: error: expected primary-expression before '/' token
   17 | if ( op == / ){ cout << x / y << endl}:
      |            ^
a.cc:17:14: error: expected primary-expression before ')' token
   17 | if ( op == / ){ cout << x / y << endl}:
      |              ^
a.cc:17:17: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   17 | if ( op == / ){ cout << x / y << 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:17:34: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   17 | if ( op == / ){ cout << x / y << endl}:
      |                                  ^~~~
      |                                  std::endl
/usr/include/c++/14/ostream:744:5: note: 'std::endl' declared here
  744 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
a.cc:17:39: error: expected primary-expression before ':' token
   17 | if ( op == / ){ cout << x / y << endl}:
      |                                       ^