/in/foo.cc: In function 'long long int digit(long long int, int)':
/in/foo.cc:14:9: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return ret;
         ^~~
/in/foo.cc:12:8: warning: 'cnt' may be used uninitialized in this function [-Wmaybe-uninitialized]
   cnt++;
        ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:12:8: warning: 'cnt' may be used uninitialized in this function [-Wmaybe-uninitialized]
   cnt++;
        ^
/in/foo.cc:5:6: note: 'cnt' was declared here
  int cnt;
      ^~~