/in/foo.cc: In function 'int main()':
/in/foo.cc:19:16: warning: unused variable 'xx2' [-Wunused-variable]
      int xx1=0,xx2=0;
                ^~~
/in/foo.cc:36:17: warning: iteration 8 invokes undefined behavior [-Waggressive-loop-optimizations]
          if(ff[i]!=9)
             ~~~~^
/in/foo.cc:35:19: note: within this loop
      for(int i=1;i<=9;i++){   
                  ~^~~