#*A small script to check the sum of a number's digits recursively
(until single digit of length). 

#p This unnamed module begins the perl source.
   use strict;
   use warnings;
   #<Main Program#>
   #<subroutine to sum the digits recursively#>

# The Main Program.
  Here we define the main program. 
  We declare a variable, |$total1|, to handle 
  the value returned from the subroutine |sub1|. In this 
  example version of the program we are only going to 
  exam the number 1818 to demonstrate
  that we get the correct result of 9. If we do get this 
  result than we |print| a confirmation. Note also the use 
  of |perlWEB|'s macro ability.
  
  #d TEST_NUMBER=1818
  
#<Main Program#>=
   my $tota11;

   for my $num (TEST_NUMBER..TEST_NUMBER){   
      my $tota11 = &spl($num);             
      print "$num == 9\n" if ($tota11 == 9);
   }

# The subroutine that handles all of the essential computation.  
  The algorithm is as follows:<br>
  &#8226;		|$total|=the sum of the digits of what is 
expected to be the sole(or first) argument to |sp1|<br>
  &#8226;		if |$total| has 1 digit then print it out<br>
  otherwise&#8230;<br>
  &#8226;		call |sp1| again with |$total| as the argument
#<subroutine to sum the digits recursively#>=
   sub spl{
      my ($num1) =@_;    #we can still have inline comments as well.
      my $total = 0;
      $total = $total + $_ for (split '', $num1);#here $total is 
                             #the sum of all the digits of $num1
      my $len = length ($total);
      return $total if ($len == 1);
      &spl($total) if ($len != 1);
   }

##</code><code>##







use strict;
use warnings;
my $tota11;

for my $num (1818..1818){   
  my $tota11 = &spl($num);             
  print "$num == 9\n" if ($tota11 == 9);
}

sub spl{
  my ($num1) =@_;    #we can still have inline comments as well.
  my $total = 0;
  $total = $total + $_ for (split '', $num1);#here $total is the 
                                 #sum of all the digits of $num1
  my $len = length ($total);
  return $total if ($len == 1);
  &spl($total) if ($len != 1);
}