fctr_in_ft

#include <stdio.h>

int ff(int a)
{
  int runner = 1;
  int b = a;
  if (a == 0)
    {
      return (1);
    }
  else if ((a > 0) && (a < 13))
    {
      while (runner < b)
    {
      a = a * runner;
      runner = runner + 1;
    }
    }
  else if ((a < 0) || (a > 12))
    {
      return (0);
    }
  return (a);
}

main ()
{
  int a = 0;
  ff(a);
  printf("%d", ff(a));
}