Critter.pm

package Critter;
use strict;
use warnings;
use v5.18;

# Critter
our $VERSION = '1.00';
#
# Inheritance
# our @ISA = qw/Animal/;


my $secret_method = sub {
	say "called from within critter";
};


sub new {
	my ( $cls, $name ) = @_;
	my $self = {
		name => $name,
		count => 0,
	};

	bless $self, $cls;
	return $self;
}

sub hello {
	my ( $self ) = @_;
	say "Hello ", $self->{name};
	$self->{count}++;
}

sub people_met {
	my ( $self ) = @_;
	say $self->{count};
}

sub DESTROY {
	my ( $self ) = @_;
	use Data::Dumper;
	print Dumper($self);
	say "this is called just before the object is destroyed";
}


1;

Hello.pm

package Hello;

use strict;
use warnings;

sub bye {
	print "goodbye cruel world\n";
}

sub hi {
	bye();
}

1;

lab1.pl

use v5.14;
use warnings;
use strict;
use Test::More tests => 4;
use MyStack;
	
MyStack::add_item(10);
MyStack::add_item(20);
MyStack::add_item(22, 33);
	
# prints 33
is(MyStack::pop_item(), 33, "Pop first item");
	
# prints 22
is(MyStack::pop_item(), 22, "Pop second item");
	
# prints 2
is(MyStack::count_items(), 2, "Item count == 2");
	
while ( MyStack::pop_item() ) {
}

is(MyStack::count_items(), 0, "Item count == 0");

lab2.pl

use v5.14;
use strict;
use warnings;

use Contacts;
use Test::More tests => 3;
use List::Util qw/first/;

my $home_book = Contacts::init();
my $work_book = Contacts::init();
	
Contacts::add_contact( $home_book, 'Tom', { lives_in => 'USA', email => '[email protected]' });
Contacts::add_contact( $home_book, 'Bob', { lives_in => 'USA', email => '[email protected]' });
	
Contacts::add_contact( $work_book, 'Mike', { lives_in => 'Mars', email => '[email protected]' });

my @result = Contacts::contacts_by_country( $home_book, 'USA' );
ok( first { $_ eq 'Tom' } @result, "Tom is in \@result");
ok( first { $_ eq 'Bob' } @result, "Bob is in \@result");
is( @result, 2, "Result has 2 items");

usemod.pl

use strict;
use warnings;
use v5.18;
use Hello;

sub bye {
	print "bye bye\n";
}

Hello::hi();