Learning Perl Objects, References amp;amp; Modules [Electronic resources] نسخه متنی

3.9 Exercises

The answers for all exercises can be found in Section A.2.

3.9.1 Exercise 1 [5 min]

How many different things do these expressions refer to?

$ginger->[2][1]
${$ginger[2]}[1]
$ginger->[2]->[1]
${$ginger->[2]}[1]

3.9.2 Exercise 2 [30 min]

Using the final version of
check_required_items, write a subroutine
check_items_for_all that takes a hash reference as
its only parameter, pointing at a hash whose keys are the people
aboard the Minnow, and whose corresponding values are array
references of the things they intend to bring on board.

For example, the hash reference might be constructed like so:

my @gilligan = ... gilligan items ...;
my @skipper = ... skipper items ...;
my @professor = ... professor items ...;
my %all = (
"Gilligan" => \@gilligan,
"Skipper" => \@skipper,
"Professor" => \@professor,
);
check_items_for_all(\%all);

The newly constructed subroutine should call
check_required_items for each person in the hash,
updating their provisions list to include the required items.