sub sum {
     my @numbers = @_;
     my $sum = 0;
     foreach my $num (@numbers){ $sum += $num }
     $sum;
  }
  print sum( 1 .. 100_000 ),"\m";

##</code><code>##

  sub sum {
     my ($numbers_ref) = @_;
     my $sum = 0;
     foreach my $num (@$numbers_ref){ $sum += $num };
     $sum;
  }
  print sum([1..100_000]), "\n";

##</code><code>##

#!/user/bin/perl
use strict;
use warnings;
use Time::HiRes qw(gettimeofday tv_interval);
sub sum {
   my ($numbers_ref) = @_;
   my $sum = 0;
   foreach my $num (@$numbers_ref){ $sum += $num };
   return $sum;
} # end sub sum()
my $t0 = [gettimeofday];
print sum([1..100_000]);
print "\n";
my $t1 = [gettimeofday];
my $elapsed = tv_interval($t0, $t1);
print "\n";
print "Elapsed time: $elapsed seconds\n";
exit(0);

##</code><code>##

   First version of sub():    0.027007 seconds
   Second version of sub():   0.024075 seconds

##</code><code>##

   First version of sum():   0.09366 seconds
   Second version of sum():  0.372829 seconds