foo.cc: In function 'int main()':
foo.cc:10:13: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'double' [-Wformat=]
   10 | printf("%.9ld",c);
      |         ~~~~^  ~
      |             |  |
      |             |  double
      |             long int
      |         %.9f

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