/in/foo.c: In function 'isPerfect':
/in/foo.c:19:5: warning: 'main' is normally a non-static function [-Wmain]
   19 | int main() {
      |     ^~~~
/in/foo.c:28:1: error: expected declaration or statement at end of input
   28 | }
      | ^
/in/foo.c:29: warning: control reaches end of non-void function [-Wreturn-type]
/in/foo.c: At top level:
/in/foo.c:19:5: warning: 'main' defined but not used [-Wunused-function]
   19 | int main() {
      |     ^~~~