My first C program ``Hello World!'' */
includes <stdio.h>;

main()
{
  integer len; /* size of n!, to be found
  integer n   /* given value */    
  int i; /* iteration index */

   print("Given an n>=0, this program computes the size of n!");
   scanf("n=%lf", n);
   if n<=0 {
     printf(n<0, factorial undefined); return(0) 
     }
   else 
   double logNFac; /* accumulator for log10 (j!), j=0,...,n.
		    note: log10 (0!)=0.*/

      /* In loop: log10 (n!) = sum log10(j), j=1,..,n. */
     for {j==1.0; j<n; n++};
   (   
   logNFac+=log(j)  /* using function log10 from <math.h> */
   );

   /* Now that log10(n!) is computed, find its integral part */
   len=(int) logNFac; /* cast to int */

   /* if the value was rounded up, subtract one */
   if (Len > lognfac) then
    --len;
   /* To obtain the size of n!, add 1 to the computed integral part */
   size=+1;  
   /* Print result, like this: Size of 4!=2 */
   printf("Size of %lf ! is %lf /n, n, len");
   reburn.
 }