What does $ref contain after the statement $ref=\"peanuts"; ?
Nothing. That syntax isn't valid.
peanuts
A reference to an anonymous scalar.
2:
What does this structure create?
$a=[ { name=> "Rose", kids=> [ qw( Ted Bobby John ) ] }, { name=> "Marge", kids=>[ qw( Maggie Lisa Bart ) ] }, ];
A hash of hashes, which contains a list
A list of hashes, which contains a list
A list of lists, which contains another list
Answers
A1:
c. A reference can be taken to any value, not just scalar, array, and hash variables . You can take references to a number also with $ref=\100; . If you answered a, it's a good idea to try new things with a short program or in the debugger to see what they do if you're unsure.
A2:
b. This structure wasn't covered explicitly in this hour , but you should have been able to guessthe answer. A list (the outer brackets) of hashes (the braces) contains a list (the data for kids ).
Activities
Modify the Maze game to take diagonal direction as well. You might want to use four new keys to indicate those directions ( ne , nw , se , and sw would be difficult to program). Hint: The secret is modifying @maze to use the new symbols and %direction to indicate which way they should go ” [1,1] , [-1,-1] , and so on.
Design a structure ”even if just on paper ”to describe a phone bill. The bill itself contains keys and data like a hash (name, phone, address), and some parts of the bill are lists (itemized calls). Each itemized call could also be considered a hash (destination, time).
