/in/foo.cc: In function 'int main()':
/in/foo.cc:199:9: warning: variable 'b1' set but not used [-Wunused-but-set-variable]
     int b1;
         ^~
/in/foo.cc:200:9: warning: variable 'b2' set but not used [-Wunused-but-set-variable]
     int b2;
         ^~