#!/usr/bin/perl -w

use strict;

my $result = factorial_recursive(5);
print "factorial_recursive(5) returns $result\n";
$result = factorial_iterative(5);
print "factorial_iterative(5) returns $result\n";

sub factorial_recursive() {
  my $n = shift;
  if ($n == 1) {
    return(1);
  } else {
    return($n * &factorial_recursive(($n - 1)));
  }
}

sub factorial_iterative() {
  my $n = shift;
  return(fi_helper(1, 1, $n));
}

sub fi_helper() {
  my ($product, $counter, $max_count) = @_;
  if ($counter > $max_count) {
    return($product);
  } else {
    return(fi_helper(($counter * $product), ($counter + 1), $max_count));
  }
}