Need a bit of help defining some methods - ruby

Question

I would really appreciate it if I could get some help on some questions regarding an assignment that prints out the data typed in by a user(In this specific example, the year, model, and make of the car):
# DEFINE YOUR CAR CLASS HERE
# create empty array
array_of_cars = Array.new
# prompt for and get number of cars
print "How many cars do you want to create? "
num_cars = gets.to_i
# create that many cars
for i in 1..num_cars
# get the make, model, and year
puts
print "Enter make for car #{i}: "
make = gets.chomp
print "Enter model for car #{i}: "
model = gets.chomp
print "Enter year of car #{i}: "
year = gets.to_i
# create a new Car object
c = Car.new
# set the make, model, and year
# that we just read in
c.set_make(make)
c.set_model(model)
c.set_year(year)
# add the Car object to the array
array_of_cars << c
end
# print out the information for
# the Car objects in the array
puts
puts "You have the following cars: "
for car in array_of_cars
puts "#{car.get_year} #{car.get_make} #{car.get_model}"
end
I already have some part of the program, but struggle with the main portion of it, since I kind of know what to do but not how to implement it.
So for this part: # DEFINE YOUR CAR CLASS HERE
I got this:
class Car
def assign(m,n,y)
#instance variables
#make = m
#model = n
#year = y
end
#instance methods
def set_make
end
def set_model
end
def set_year
end
def get_make
end
def get_model
end
def get_year
end
First, did I do it right with the instance variables?
And then, the purpose of "set" is to save the value into the array right? and then "get" allows me to extract them later. I think I would understand the concept if someone could show me how to define one of them.
I know that this seems a bit vague, so I will try my best to clarify if some questions occur. Also sorry for the wall of text and thank you!

Answer 1

In the first place, in “idiomatic ruby” we call getters and setters for #variable as variable (getter) and variable= (setter.) The constructor is to be named initialize, not assign.
There is a helper to define both for the class, Module#attr_accessor that declares both getter and setter under the hood, so that your class definition might be as short as:
class Car
attr_accessor :make, :model, :year
def initialize(make, model, year)
#make = make
#model = model
#year = year
end
end
So far so good. The rest of your code would be:
array_of_cars = [] # use Array.new with parameter, [] otherwise
# prompt for and get number of cars
print "How many cars do you want to create? "
num_cars = gets.to_i
# create that many cars
(1..num_cars).each do |i| # in idiomatic ruby, never use for loops
# get the make, model, and year
puts "Enter make for car #{i}: "
make = gets.chomp
print "Enter model for car #{i}: "
model = gets.chomp
print "Enter year of car #{i}: "
year = gets.to_i
# create a new Car object
c = Car.new(make, model, year)
# add the Car object to the array
array_of_cars << c
end
# print out the information for
# the Car objects in the array
puts
puts "You have the following cars: "
array_of_cars.each do |car|
puts "#{car.year} #{car.make} #{car.model}"
end
BTW, instead of pre-creating an array, one might better use Enumerable#map:
# prompt for and get number of cars
print "How many cars do you want to create? "
num_cars = gets.to_i
# ⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓⇓ DECLARE IT IN-PLACE
array_of_cars = (1..num_cars).map do |i|
puts "Enter make for car #{i}: "
make = gets.chomp
print "Enter model for car #{i}: "
model = gets.chomp
print "Enter year of car #{i}: "
year = gets.to_i
# create a new Car object
Car.new(make, model, year)
end
That would produce an array needed out of the box.
Addendum: to define getter and setter manually:
class Car
attr_accessor :make, :model
def initialize(make, model, year)
#make = make
#model = model
#year = year
end
# manually declare getter for year:
def year
#year
end
# manually declare setter for year:
def year=(year)
#year = year
end
end