Those comment headers seem distracting and don't add anything of value. I'd just remove them.

recursive_factorial() can also use a ternary statement:

  double recursive_factorial(double n) {
      return (n < 1) ? 1 : n * recursive_factorial(n-1);
  }

An unformatted output can be done with puts() instead of printf().

Those comment headers seem distracting and don't add anything of value. I'd just remove them.

An unformatted output can be done with puts() instead of printf().