/in/foo.cc: In function 'int main()':
/in/foo.cc:19:22: warning: format '%d' expects argument of type 'int', but argument 2 has type 'double' [-Wformat=]
   19 |             printf("%d\n", e - sum);
      |                     ~^     ~~~~~~~
      |                      |       |
      |                      int     double
      |                     %f