CODEWITHSUNDEEP
ruby-on-railsruby
jblades
jblades

Reputation: 21

`initialize': wrong number of arguments (1 for 0)

I'm getting an error with the following example when running the program.

The error reads as such:

burger.rb:8:in `initialize': wrong number of arguments (1 for 0) (ArgumentError)
    from burger.rb:19:in `new'
    from burger.rb:19:in `<main>'

Any help is appreciated for this noob, the code is below:

$toppings = false

class Burger
    AVAILABLE_TOPPINGS = ["lettuce", "tomato", "onion", "cheese"]

    attr_reader :options

    def initialize
        @toppings = []
    end

    def order
        print "how many burgers would you like? "
        number = gets.chomp
        puts "#{number} burgers coming right up boss!"
    end
end

burger = Burger.new("lettuce")

burger.order

Upvotes: 1

Views: 2447

Answers (3)

Kyle Decot
Kyle Decot

Reputation: 20835

As others have said your initializer is expecting no arguments but you're giving it lettuce. If you're using ruby 2.1 or later I would suggest using keyword arguments:

class Burger
  TOPPINGS = %i[lettuce tomato onion cheese]

  attr_reader :toppings

  def initialize(toppings: [])
    @toppings = TOPPINGS & toppings
  end
end

This allows you do to Burger.new(toppings: [:lettuce]) which I feel is a lot more readable.

Upvotes: 2

the Tin Man
the Tin Man

Reputation: 160631

$toppings = false

is code smell. Globals are generally not necessary, and should only be used when you're absolutely sure they're needed. When you're first learning an OO language I think it's better to avoid them and learn about variable scoping.

In this case, you don't use it in your sample code, but you do use:

@toppings = []

(which is again not used elsewhere). It isn't a good idea to name a global variable the same as an instance variable because it's too easy to use one when you mean the other, and introduce a bug.

Upvotes: 0

Yu Hao
Yu Hao

Reputation: 122503

The error is telling you that the method initialize expects 0 argument, while you give it 1 ("lettuce" in Burger.new("lettuce")).

You need to make initialize expecting one argument:

def initialize(options)
    @toppings = []
    @options = options
end

Upvotes: 2

Related Questions