Simple code doesnt work

ruby-talk
1

Hi everyone,

Can anyone tell me why this doesnt work?

Im getting this error
cf.rb:26: undefined method `price' for #<Ticket:0x27ed554
@d="11/12/2006", @price=5.0, @v="yer"> (NoMethodError)

thanks, just learning :slight_smile:

class Ticket

  def initialize(venue,date)
    @v = venue
    @d = date
  end

  def venue
    @v
  end

  def date
    @d
  end

  def price=(amount)
    @price = amount
  end
end

ticket = Ticket.new("yer","11/12/2006")
puts "ticket stuff is #{ticket.venue} #{ticket.date}"

ticket.price = (5.00)

puts "ticket mooch is #{ticket.price}"

···

--
Posted via http://www.ruby-forum.com/.

2

Hello Vince :wink: !

Im getting this error
cf.rb:26: undefined method `price' for #<Ticket:0x27ed554
@d="11/12/2006", @price=5.0, @v="yer"> (NoMethodError)

thanks, just learning :slight_smile:

class Ticket
      [...]
  def price=(amount)
    @price = amount
  end
end

ticket = Ticket.new("yer","11/12/2006")
puts "ticket stuff is #{ticket.venue} #{ticket.date}"

ticket.price = (5.00)

puts "ticket mooch is #{ticket.price}"

  You define the price= method, but you don't define the price method.
You can't access to instance variables from outside the instance unless
you explicitly allow it via appropriate accessors. In your case,
replacing the price= definition by

attr_accessor :price

should work pretty well. You might want to use attr_reader to only grant
read acces to an instance variable or attr_writer to only grant write
access.

  Enjoy !

  Vince (yet another one...)

3

Hey,

Vince /. wrote:

Hi everyone,

Can anyone tell me why this doesnt work?

*snip*

Sure, where you've got a method "price=(amount)", below:

  def price=(amount)
    @price = amount
  end
  

this only handles the assigning of the price variable. This means that:

ticket.price = (5.00)
  

works fine, but trying to access ticket.price results in the error you're seeing (hence why the error doesn't occur on the above line, but on a later line). You simply need a method declaration for retrieving the variable value within your class, so try putting this in there:

def price
    @price
end

This then ensures you've got one method ("price=") that handles the assignation of values, and one method ("price") to retrieve the current value.

Your following code should then work:

puts "ticket mooch is #{ticket.price}"

Hope that helps!

Cheers,
-= El =-

blog: http://www.crazycool.co.uk

4

Hi everyone,

Can anyone tell me why this doesnt work?

Im getting this error
cf.rb:26: undefined method `price' for #<Ticket:0x27ed554
@d="11/12/2006", @price=5.0, @v="yer"> (NoMethodError)

thanks, just learning :slight_smile:

class Ticket

        def initialize(venue,date)
                @v = venue
                @d = date
        end

        def venue
                @v
        end

        def date
                @d
        end

        def price=(amount)
                @price = amount
        end
end

ticket = Ticket.new("yer","11/12/2006")
puts "ticket stuff is #{ticket.venue} #{ticket.date}"

ticket.price = (5.00)

puts "ticket mooch is #{ticket.price}"

You need to define attribute reader:

def price
  @price
end

BTW, you could accomplish the same by using
attr_reader(R)/attr_writer(W)/attr_accessor(RW):
(if you'd rename @v, @d to @venue, @date respectively)

class Ticket

        def initialize(venue,date)
                @venue, @date = venue, date
        end

           attr_reader :venue, :date # this will create venue() and date()
           attr_accessor :price # this will create price=() and price()

···

On 9/20/06, Vince /. <totalharmonicdistortion@hotmail.com> wrote:

end

5

Vince /. wrote:

  def price=(amount)
    @price = amount
  end
end

Hi there,

You have a price= method defined, but not a price method. So when you
say ticket.price there is no method for that.

Try this in your class:

def price
  @price
end

Regards,
Jordan