printf("\nx = %4.1f   exp = %12.5E  series = %12.5E
              number of terms = %d",
              x, exp(-x), sum, n);
   } // end of for() loop

   printf("\n");           // a final line shift on output
   return 0;
} // End: function main()
//     The function factorial()
//     calculates and returns n!
TYPE factorial(int n)
{
   int  loop;
   TYPE fac;
   for(loop = 1, fac = 1.0; loop <= n; loop++)  {
      fac *= loop;

   return fac;
} // End: function factorial()