/in/foo.cc: In function 'void print_a()':
/in/foo.cc:19:9: warning: empty parentheses were disambiguated as a function declaration [-Wvexing-parse]
   19 | int main()
      |         ^~
/in/foo.cc:19:9: note: remove parentheses to default-initialize a variable
   19 | int main()
      |         ^~
      |         --
/in/foo.cc:19:9: note: or replace parentheses with braces to value-initialize a variable
/in/foo.cc:20:1: error: a function-definition is not allowed here before '{' token
   20 | {
      | ^
/in/foo.cc:24:2: error: expected '}' at end of input
   24 | }
      |  ^
/in/foo.cc:5:1: note: to match this '{'
    5 | {
      | ^