foo.cc: In function 'int main()':
foo.cc:8:6: warning: variable 'a' set but not used [-Wunused-but-set-variable]
  int a,b,c,d,e,f,i;
      ^
foo.cc:8:12: warning: unused variable 'd' [-Wunused-variable]
  int a,b,c,d,e,f,i;
            ^

[Hydro](https://hydro.ac)提供评测服务