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我想创建一个程序，用户基本上“创建”一个购物清单，用户在其中输入商品和价格，直到他们想要退出。如果用户输入“q”或“Q”，那么程序应该停止提示用户，而是应该计算小计，加上名义上的 6% 销售税，并显示总结果。

我得到了第一部分，用户输入他们的项目和价格，但我不知道如何让它告诉我小计并给他们一张收据。我已经尝试了7个小时！！当我运行它时，它应该说：

Enter an item and its price, or ’Q/q’ to quit: eggs 2.13
Enter an item and its price, or ’Q/q’ to quit: milk 1.26
Enter an item and its price, or ’Q/q’ to quit: batteries 3.14
Enter an item and its price, or ’Q/q’ to quit: q
Receipt:
--------
eggs => $2.13
milk => $1.26
batteries => $3.14
---------
subtotal: $6.53
tax: $0.39
total: $6.92

这是我制作的代码：（有人可以帮我吗？？？）

def create_list
puts 'Please enter item and its price or type "quit" to exit'
items = gets.chomp.split(' ')
grocery_list  = {}
index = 0 
until index == items.length
grocery_list[items[index]] = 1 
index += 1
end
grocery_list
end

def add_item (list)
items  = ''
until items == 'quit'
puts "Enter a new item & amount, or type 'quit'."
items = gets.chomp
if items != 'quit'
  new_item = items.split(' ')
  if new_item.length > 2
    #store int, delete, combine array, set to list w/ stored int
    qty = new_item[-1]
    new_item.delete_at(-1)
    new_item.join(' ')
    p new_item
  end
  list[new_item[0]]  = new_item[-1]
else
  break
end
end
list
end

 add_item(create_list)

 puts "Receipt: "
 puts "------------"
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1 回答 1

1

不确定您是否需要哈希，因为它们用于存储键值对。此外，您应该在定义变量的地方组织代码，然后是方法，然后最后运行代码。保持方法简单。

#define instance variabes so they can be called inside methods
@grocery_list = [] # use array for simple grouping. hash not needed here
@quit = false # use boolean values to trigger when to stop things.
@done_shopping = false
@line = "------------" # defined to not repeat ourselves (DRY)

#define methods using single responsibility principle.
def add_item
  puts 'Please enter item and its price or type "quit" to exit'
  item = gets.chomp
  if  item == 'quit'
    @done_shopping = true
  else
    @grocery_list << item.split(' ')
  end
end

# to always use 2 decimal places
def format_number(float)
  '%.2f' % float.round(2)
end

#just loop until we're done shopping.
until @done_shopping
  add_item
end

puts "\n"
#print receipt header
puts "Receipt: "
puts @line

#now loop over the list to output the items in arrray.
@grocery_list.each do |item|
  puts "#{item[0]} => $#{item[1]}"
end

puts @line
# do the math
@subtotal = @grocery_list.map{|i| i[1].to_f}.inject(&:+) #.to_f converts to float
@tax = @subtotal * 0.825
@total = @subtotal + @tax

#print the totals
puts "subtotal: $#{format_number @subtotal}"
puts "tax: $#{format_number @tax}"
puts "total: $#{format_number @total}"
#close receipt
puts @line
于 2017-10-07T06:52:40.680 回答