answer.code:19:26: error: stray ‘\’ in program
   19 |            cout<<?invalid\n?;
      |                          ^
answer.code: In function ‘int main()’:
answer.code:19:18: error: expected primary-expression before ‘?’ token
   19 |            cout<<?invalid\n?;
      |                  ^
answer.code:19:19: error: ‘invalid’ was not declared in this scope
   19 |            cout<<?invalid\n?;
      |                   ^~~~~~~
answer.code:19:26: error: expected ‘:’ before ‘n’
   19 |            cout<<?invalid\n?;
      |                          ^~
      |                          :
answer.code:19:27: error: ‘n’ was not declared in this scope
   19 |            cout<<?invalid\n?;
      |                           ^
answer.code:19:29: error: expected primary-expression before ‘;’ token
   19 |            cout<<?invalid\n?;
      |                             ^
answer.code:19:29: error: expected ‘:’ before ‘;’ token
   19 |            cout<<?invalid\n?;
      |                             ^
      |                             :
answer.code:19:29: error: expected primary-expression before ‘;’ token
answer.code:107:2: error: expected ‘}’ at end of input
  107 | }
      |  ^
answer.code:6:12: note: to match this ‘{’
    6 | int main() {
      |            ^