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Learn to Program, 2nd Edition
book

Learn to Program, 2nd Edition

by Chris Pine
March 2009
Intermediate to advanced content levelIntermediate to advanced
194 pages
4h
English
Pragmatic Bookshelf
Content preview from Learn to Program, 2nd Edition

Creating Classes

We’ve now seen a smattering of different classes. However, it’s easy to come up with kinds of objects that Ruby doesn’t have—objects you’d like it to have. Fear not; creating a new class is as easy as extending an old one. Let’s say we wanted to make some dice in Ruby, for example. Here’s how we could make the Die class:

class​ Die
def​ roll
1 + rand(6)
end
end
# Let's make a couple of dice...
dice = [Die.new, Die.new]
# ...and roll them.
dice.each ​do​ |die|
puts die.roll
end
4
2

(If you skipped the section on random numbers, rand(6) just gives a random number between 0 and 5.) And that’s it! These are objects of our very own. Roll the dice a few times (run the program again), and watch what turns up.

We can define all ...

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Publisher Resources

ISBN: 9781680500172Errata