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

my $firstname = "Jonathan";

print "Hello, $firstname\n";

$firstname = "John";

print "Goodbye, $firstname\n";


my $variable = "\0";
my $another_variable = 2;
my @array_variable = qw(one two three);

$variable = 3;
print "$variable\n";
$variable = 3.1415926;
print "$variable\n";
$variable = 3.402823669209384634633e+38;
print "$variable\n";
$variable = $another_variable + 1;
print "$variable\n";
$variable = 'Can contain text';
print "$variable\n";
$variable = \$another_variable;
print "$variable\n";
$variable = \@array_variable;
print "$variable\n";


my @Array1 = (1, 2, 3);
my @Array2 = (4, 5, 6);
my @Array3 = (7, 8, 9);

@array_variable = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
print "@array_variable\n";
@array_variable = (1 .. 10);
print "@array_variable\n";
@array_variable = ('John', 'Paul', 'George', 'Ringo');
print "@array_variable\n";
@array_variable = qw/John Paul George Ringo/;
print "@array_variable\n";
@array_variable = qw/red blue 1 green 5/;
print "@array_variable\n";
@array_variable = (\@Array1, \@Array2, \@Array3);
print "@array_variable\n";

my $idx = 2;

$array_variable[0] = 1;
print "@array_variable\n";
$array_variable[$idx] = 1;
print "@array_variable\n";

my %hash = (
    'key1' => 'value1',
    'key2' => 'value2',
    'key3' => 'value3',
);
print %hash, "\n";

$hash{'key1'} = 'newval1';
print %hash, "\n";


sub fib {
    my $n = shift();
    return $n if $n < 2;
    return fib($n - 1) + fib($n - 2);
}

print fib(14), "\n";