ruby: undefined local variable or method 'car' -- fixing syntax errors - ruby

Question

I have a few syntax errors on my program that are really bothering me. I can't seem to figure out how to fix them as I am new to ruby. The first error is on the title, I have a few more I'm sure. The purpose of the program is to create cars with make, model, and year and have user input how many cars they want then display all of them at the end.
Can someone point me to the right direction?
Here is my code:
class Car
def initialize(make, model, year)
#make = make
#model = model
#year = year
end
print "How many cars do you want to create? "
array_of_cars = Array.new
num_cars = gets.to_i
c = car.new
for i in 1..num_cars
end
puts
print "Enter make for car #{i}: "
make = gets.chomp
print "Enter model for car #{i}: "
model = gets.chomp
print "Enter year for car #{i}: "
year = gets.to_i
c.set_make(make)
c.set_model(model)
c.set_year(year)
array_of_cars << c
end
puts
puts "You have the following cars: "
for car in array_of_cars
puts "#{car.get_year} #{car.get_make} #{car.get_model}"
end

Answer 1

In ruby, class names are constants, so should start with a capital letter, as in class Car. When creating a new object of that class, you call new on the class itself. So you would change car.new into Car.new.
You will also need to define your set_* and get_* methods inside the class, but since this is a common pattern, ruby has attr_accessor available. See this answer for a full explanation of attr_accessor.

Answer 2

Consider that your Car does not do anything, it contains only data and has no methods. When this happens, consider making it a Struct instead of a class. A Struct generates a reader and writer method automatically without even specifying attr_reader.
Car = Struct.new(:make, :model, :year)
array_of_cars = Array.new
while true
puts
print "Enter make for car ('x' to exit): "
make = gets.chomp
break if make == 'x'
print "Enter model for car: "
model = gets.chomp
print "Enter year for car: "
year = gets.to_i
array_of_cars << Car.new(make, model, year)
end
puts
puts 'You have the following cars:' # sorted by year for fun
array_of_cars.sort_by{ | car | car.year }.each do | car |
puts "#{car.year} #{car.make} #{car.model}"
end

Answer 3

A few pieces of advice.
Run Ruby with the -w option :
$ ruby -w cars.rb
cars.rb:17: warning: mismatched indentations at 'end' with 'for' at 16
cars.rb:34: warning: mismatched indentations at 'end' with 'class' at 1
cars.rb:41: warning: mismatched indentations at 'end' with 'for' at 39
and eliminate the cause of warnings.
$ ruby -w cars.rb
How many cars do you want to create? 2
cars.rb:2:in `initialize': wrong number of arguments (given 0, expected 3) (ArgumentError)
from cars.rb:13:in `new'
from cars.rb:13:in `<main>'
new calls initialize, so new must have the same number of arguments
as parameters in initialize. Hence a car can be created only after you have asked all the information.
Don't work in the class. As written, your code is executed when Ruby reads
the class definition. For this exercise, you can leave it in the main level outside the class definition, or put it into a method.
for i in 1..num_cars
end
This loop is empty and does nothing. And prefer powerful iterators instead of this C, Perl, Java style (for, while, etc).
I define strings with apostrophes and keep double quotes when interpolation is needed (even if it's a question of nano seconds and personal choice). See here and there.
If you want to be comfortable with Ruby programming, I recommend The Pickaxe.
There are many ways of doing things in Ruby. The following is one solution.
class Car
attr_reader :make, :model, :year
def initialize(make, model, year)
#make = make
#model = model
#year = year
end
def self.make_car # class method (more precisely : singleton method)
print 'How many cars do you want to create? '
array_of_cars = Array.new
num_cars = gets.to_i
num_cars.times do | i |
real_index = i + 1
puts
print "Enter make for car #{real_index}: "
make = gets.chomp
print "Enter model for car #{real_index}: "
model = gets.chomp
print "Enter year for car #{real_index}: "
year = gets.to_i
=begin
c = Car.new(make, model, year)
array_of_cars << c
=end
# some will tell you to avoid unnecessary variables ...
array_of_cars << Car.new(make, model, year)
end
puts
puts 'You have the following cars:' # sorted by year for fun
array_of_cars.sort_by{ | car | car.year }.each do | car |
puts "#{car.year} #{car.make} #{car.model}"
end
end
end # class Car
Car.make_car