/in/foo.cc: In function 'int main()':
/in/foo.cc:34:9: warning: unused variable 'j' [-Wunused-variable]
     int j=i-1;
         ^
/in/foo.cc:21:3: warning: 'face' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(face==1)
   ^~