/in/foo.cc: In function 'int main()':
/in/foo.cc:27:9: warning: variable 's' set but not used [-Wunused-but-set-variable]
     int s;
         ^
/in/foo.cc: In function 'bool isp(int)':
/in/foo.cc:20:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^