/in/foo.cc: In function 'int main()':
/in/foo.cc:43:23: warning: value computed is not used [-Wunused-value]
   delete[] f[i], ans[i];
                  ~~~~~^
/in/foo.cc:43:23: warning: right operand of comma operator has no effect [-Wunused-value]
/in/foo.cc:44:17: warning: right operand of comma operator has no effect [-Wunused-value]
  delete[] a, f, ans;
                 ^~~
/in/foo.cc:44:20: warning: right operand of comma operator has no effect [-Wunused-value]
  delete[] a, f, ans;
                    ^