everyone, I'm a super Ruby n00b having problems getting my first Ruby program to work. I have found Q and A here on Stack Overflow that are closely related to the problem that I am having but no matter what I try, I just can't get rid of this error.
I have written two classes, Checkout and Register. Here's the full Register class:
<code>
load 'Register.rb'
class Checkout
def initialize
@register = Register.new
@itemCount = Hash['CH1', 0, 'AP1', 0, 'CF1', 0, 'MK1', 0]
@@inventory = Hash['CH1', 3.11, 'AP1', 6.00, 'CF1', 11.23, 'MK1', 4.75]
@@discount = Hash['CF1', ['BOGO', '@itemCount["CF1"]%2==0', -11.23, '@register.findLast("CF1")'], 'AP1', ['APPL', '@itemCount["AP1"]>=3', -1.50, '@itemCount["AP1"]==3 ? @register.findAll("AP1") : @register.findLast("AP1")'], 'MK1', ['CHMK', '@itemCount["MK1"]==1 && @itemCount["CH1"]==1', -4.75, '@register.findAll("MK1")']]
end
def scan(item)
#get price of item from inventory
price = @@inventory[item]
#add item and price to register
@register.ringUp(item, price)
@itemCount[item]+=1
#find and apply any applicable special
discountCheck = @@discount[item]
unless discountCheck == nil
nameOfDiscount = @@discount[item][0]
discountCondition = @@discount[item][1]
moneyOff = @@discount[item][2]
howToGetItemIndex = @@discount[item][3]
if(eval(discountCondition))
ind = eval(howToGetItemIndex)
if(ind.class == "Array")
@register.applyDiscount(ind, moneyOff, nameOfDiscount)
else #it's a Fixnum so we want to put it in an array first
indArray = [ind]
@register.applyDiscount(indArray, moneyOff, nameOfDiscount)
end
end
end
end
end
</code>
Here is the Register class:
<code>
class Register
def initialize
@itemsInOrderOfScan = Array.new
@itemInfoInOrderOfScan = Array.new
end
def ringUp(item, price)
@itemsInOrderOfScan.push(item)
@itemInfoInOrderOfScan.push(['', price])
end
def applyDiscount(indices, moneyOff, nameOfDiscount)
for i in 0..indices.length-1
ind = indices[i]
newInd = ind + 1
@itemsInOrderOfScan.insert(newInd, '')
@itemInfoInOrderOfScan.insert(newInd, [nameOfDiscount, moneyOff])
end
end
def findLast(item)
arr = Array.new
ind = @itemsInOrderOfScan.rindex(item)
arr.push(ind)
arr
end
def findAll(item)
indexOfFirstInstanceOfItem = @itemsInOrderOfScan.index(item)
arr = findLast(item)
indexOfLastInstanceOfItem = arr.at(0)
for i in indexOfFirstInstanceOfItem..indexOfLastInstanceOfItem
if(@itemsInOrderOfScan.at(i) == item)
arr.push(i)
end
end
arr
end
def printReceipt
puts "Item\t\t\tPrice"
puts "----\t\t\t-----"
total = 0
for i in 0..@itemsInOrderOfScan.length-1
currentItem = @itemsInOrderOfScan.at(i)
currentDiscountName = @itemInfoInOrderOfScan.at(i)[0]
currentPrice = @itemInfoInOrderOfScan.at(i)[1]
total += currentPrice
puts "#{currentItem}\t#{currentDiscountName}\t\t#{currentPrice}"
end
puts "-----------------------------------\n\t\t\t#{total}"
end
end
</code>
The way these classes should work when I try to run them is as follows: I feed Checkout various items and the two classes work together to create a receipt showing what has been purchased and any discounts that could be applied whenever I call the printReceipt method.
The test that I am using to debug looks like this:
<code>
load 'Checkout.rb'
basket = ['CH1', 'AP1', 'AP1', 'AP1', 'MK1']
co = Checkout.new
for i in 0..basket.length
puts basket.at(i)
co.scan(basket[i])
end
co.register.print()
</code>
The output when I run the test looks like this:
<code>
CH1
AP1
AP1
AP1
Register.rb:16:in `+': no implicit conversion of Fixnum into Array (TypeError)
from Register.rb:16:in `block in applyDiscount'
from Register.rb:14:in `each'
from Register.rb:14:in `applyDiscount'
from Checkout.rb:33:in `scan'
from main.rb:9:in `block in <main>'
from main.rb:7:in `each'
from main.rb:7:in `<main>'
</code>
Please help!
Thank you in advance.
you need to fix at 4 places,
In Checkout.rb
, if(ind.class == "Array")
is wrong comparison
use if(ind.class.to_s == "Array")
or better use if(ind.instance_of? Array)
In you main.rb
, use for i in 0...basket.length
instead of for i in 0..basket.length
because 1..2
=> [1,2] but 1...3
=> [1,2]
In Checkout.rb
, after Class first line should be attr_accessor :register
because you are access register in main.rb
In main.rb
, co.register.printReceipt
instead of co.register.print()
main.rb :
load 'Checkout.rb'
basket = ['CH1', 'AP1', 'AP1', 'AP1', 'MK1']
co = Checkout.new
for i in 0...basket.length
puts basket.at(i)
co.scan(basket[i])
end
co.register.printReceipt
Checkout.rb :
load 'Register.rb'
class Checkout
attr_accessor :register
def initialize
@register = Register.new
@itemCount = Hash['CH1', 0, 'AP1', 0, 'CF1', 0, 'MK1', 0]
@@inventory = Hash['CH1', 3.11, 'AP1', 6.00, 'CF1', 11.23, 'MK1', 4.75]
@@discount = Hash['CF1', ['BOGO', '@itemCount["CF1"]%2==0', -11.23, '@register.findLast("CF1")'], 'AP1', ['APPL', '@itemCount["AP1"]>=3', -1.50, '@itemCount["AP1"]==3 ? @register.findAll("AP1") : @register.findLast("AP1")'], 'MK1', ['CHMK', '@itemCount["MK1"]==1 && @itemCount["CH1"]==1', -4.75, '@register.findAll("MK1")']]
end
def scan(item)
#get price of item from inventory
price = @@inventory[item]
#add item and price to register
@register.ringUp(item, price)
p item
p @itemCount[item]
@itemCount[item]+=1
#find and apply any applicable special
discountCheck = @@discount[item]
unless discountCheck == nil
nameOfDiscount = @@discount[item][0]
discountCondition = @@discount[item][1]
moneyOff = @@discount[item][2]
howToGetItemIndex = @@discount[item][3]
if(eval(discountCondition))
ind = eval(howToGetItemIndex)
if(ind.class.to_s == "Array")
@register.applyDiscount(ind, moneyOff, nameOfDiscount)
else #it's a Fixnum so we want to put it in an array first
indArray = [ind]
@register.applyDiscount(indArray, moneyOff, nameOfDiscount)
end
end
end
end
end