/in/foo.cc: In function 'bool comp(xx, xx)':
/in/foo.cc:20:9: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
   20 | int main()
      |         ^~
/in/foo.cc:20:9: note: remove parentheses to default-initialize a variable
   20 | int main()
      |         ^~
      |         --
/in/foo.cc:20:9: note: or replace parentheses with braces to value-initialize a variable
/in/foo.cc:21:1: error: a function-definition is not allowed here before '{' token
   21 | {
      | ^
/in/foo.cc:33:2: error: expected '}' at end of input
   33 | }
      |  ^
/in/foo.cc:12:1: note: to match this '{'
   12 | {
      | ^