CODEWITHSUNDEEP
ruby-on-railsruby
SG17
SG17

Reputation: 41

Wrong return value when calling a method

I need to Add a tractor_beam instance method that takes a string description of an item as a parameter (e.g., "cow"). When called, the method should disable the shield, add the item to the inventory along with the ship's current location if it isn't too heavy to pick up (see algorithm below), enable the shield again, and return true. If the item is too heavy to pick up, the method should skip the inventory update and return false.

Algorithm:

An item is too heavy to pick up if its letters add up to more than 500. using .ord (Not very scientific, i know.) For example, the letters of cow add up to 329, so our tractor beam can abduct a cow, no problem.

My problem is that it returns nil and an empty hash, how do i break down the item to add each together?

Code:

class Spaceship
  attr_accessor :name, :location, :item, :inventory
  attr_reader :max_speed

  def initialize (name, max_speed, location)
    puts "Initializing new Spaceship"
    @name = name
    @max_speed = max_speed
    @location = location
    @item = item
    @inventory = {}
   end

  def disable_shield
    puts "Shield is off!"
   end

  def enable_shield
    puts "Shield is on!"
   end

  def warp_to(location)
     puts "Traveling at #{max_speed} to #{location}!"
     @location = location
   end

  def tractor_beam(item)
    disable_shield

    item = item.split('')

    item.each do |let|
      let.ord
      let + let.next
    end

    return item

    if item > 500
      enable_shield
      @inventory[@location] = item
      return true
     else
      return false
      end
    end
 end

Driver Code:

uss_enterprise = Spaceship.new("USS Enterprise","200,000 mph", "China")

hms_anfromeda = Spaceship.new("HMS Andromeda", "108,277 mph", "China")

uss_enterprise.disable_shield
hms_anfromeda.enable_shield

p hms_anfromeda.location

hms_anfromeda.warp_to("Namibia")

p hms_anfromeda.location

hms_anfromeda.tractor_beam("cow")

p hms_anfromeda.item

Terminal:

Initializing new Spaceship
Initializing new Spaceship
Shield is off!
Shield is on!
"China"
Traveling at 108,277 mph to Namibia!
"Namibia"
Shield is off!
nil

Upvotes: 0

Views: 124

Answers (2)

C dot StrifeVII
C dot StrifeVII

Reputation: 1885

This line return item in your tractor_beam method will get run every time before getting to your if statement I think that is causing the problem.

Also you are not using the instance variable @item that you are created in the initialize method I think you might actually want something like this:

def tractor_beam(item)
  disable_shield

  @item = item.split('')
  weight = 0

  @item.each do |let|
    weight += let.ord   
  end

  if weight < 500
    enable_shield
    @inventory[@location] = @item
    return true
   else
    return false
    end
  end
end

Upvotes: 1

Cjmarkham
Cjmarkham

Reputation: 9681

Firstly, you have a return statement before your if conditional, so the conditional will never be ran. Remove that. Secondly, you get the weight of the item by using ord, but you aren't assigning the value to anything: 

item.each do |let|
  let.ord
  let + let.next
end

return item

if item > 500

This should do the trick:

item = item.split('')
weight = 0

item.each do |let|
  weight += let.ord # add the ord of this letter to the weight
end

if weight > 500 # weight is now the ord of each letter of item 'cow'
  enable_shield
  @inventory[@location] = item
  return true
else
  return false
end

Upvotes: 1

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