#!/usr/bin/perl
use warnings;
use strict;

my $foo = 'bar';
my $x = 17;
# print "DEBUG: x is '$x' outside \n";
{
  my $x = 18;
  # print "DEBUG: x is '$x' inside \n";
}
# print "DEBUG: x is still '$x' outside \n" if $DEBUG;
print "Done.\n";

my $s = sum(10,20,3);   # Find the sum of three numbers.
print "the sum is '$s'\n";

my $deoxyribonucleic = 'aaagttctaactd';

print "answer is '$deoxyribonucleic' \n";

# ------------------
# Usage: $s = sum(1,2,3);   
# Retunrs sum of up to three numbers.
sub sum {
  
}
# ------------------

