/in/foo.cc: In function 'int main()':
/in/foo.cc:4:17: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
    4 |         int main()
      |                 ^~
/in/foo.cc:4:17: note: remove parentheses to default-initialize a variable
    4 |         int main()
      |                 ^~
      |                 --
/in/foo.cc:4:17: note: or replace parentheses with braces to value-initialize a variable
/in/foo.cc:5:1: error: a function-definition is not allowed here before '{' token
    5 | {
      | ^
/in/foo.cc:20:2: error: expected '}' at end of input
   20 | }
      |  ^
/in/foo.cc:3:11: note: to match this '{'
    3 | int main(){
      |           ^