/in/foo.cc: In function 'int main()':
/in/foo.cc:40:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<strlen(s);i++)
              ~^~~~~~~~~~
/in/foo.cc: In function 'int f(char)':
/in/foo.cc:12:3: warning: control reaches end of non-void function [-Wreturn-type]
   }
   ^