Learning Exercise
A ternary conditional is a shorter way of writing simple if/else statements.
If an if/else statement contains only two branches, one for when the condition is true and one for when it is false, it can be re-written as a ternary conditional.
Ternaries use a combination of the ? and : symbols to split up a conditional:
condition ? true_branch : false_branch
The code on the left side of the ? is the condition and the code on the right contains the two possible branches, separated by the :.
If the condition is true, the code on the left side of the : is executed.
If the condition is false, then the code on the right of the : gets executed.
For example:
if traffic_light == 'green'
cross_the_road
else
wait
end
can be re-written as:
traffic_light == 'green' ? cross_the_road : wait
In this exercise you will build out rules for a movie theater's website.
The theatre offers a discount for "old-age-pensions". Anyone who is 60 or older pays 10.00 for a ticket. Anyone younger pays the full 15.00.
Write the Moviegoer#ticket_price method using a ternary statement.
Moviegoer.new(21).ticket_price
#=> 15
Moviegoer.new(65).ticket_price
#=> 10
The cinema has a simplified age-verification system. If you are 18 or over you can watch scary movies. If you are younger, you cannot.
Implement the Moviegoer.watch_scary_movie? method.
It should return whether someone is allowed to watch the movie or not.
Moviegoer.new(21).watch_scary_movie?
#=> true
Moviegoer.new(17).watch_scary_movie?
#=> false
The cinema has a Movie Club program. Members get free popcorn when they watch any movie.
Implement the Moviegoer.claim_free_popcorn! method.
If a viewer is a movie club member, they should be rewarded with their free popcorn.
If they are not, the method should raise the NotMovieClubMemberError exception defined at the top of the code.
Moviegoer.new(21, member: true).claim_free_popcorn!
#=> 🍿
Moviegoer.new(17, member: false).claim_free_popcorn!
#=> Exception was raised! (NotMovieClubMemberError)
Edit via GitHub
Sign up to Exercism to learn and master Ruby with 20 concepts, 118 exercises, and real human mentoring, all for free.