Question

我正在尝试解决这个非常基本的挑战。在我开始添加订单的总利润之前，其他所有方法都运行良好，并且收到错误消息：“ challange3.rb：64：in <main>': undefined method +'for nil：NilClass（NoMethodError）”。

挑战3：调酒师挑战

您正在一家酒吧里工作，那里有当前积压的饮料：

3杯鸡尾酒， 2水和 6杯啤酒编写一个程序询问客户的订单。

如果他们订购鸡尾酒，则在需要制作的鸡尾酒数量上加一个。如果他们订购了水，则在需要添加的水数量上加一。如果他们订购啤酒，则在倒入的啤酒数量中加一。打印最终的饮料订单，以便您知道该怎么做。鸡尾酒的售价为22美元，制作成本为8美元。啤酒的售价为12美元，倒出的价格为3美元。水的售价为6美元，制造成本为0.15美元。打印出您的订单的总利润。

这是我的代码

backlog_cocktails = 3
backlog_waters = 2
backlog_beers = 6

cocktail_cost = 8
water_cost = 0.15
beer_cost = 3

cocktail_selling_price = 22
water_selling_price = 6
beer_selling_price = 12

total_profit = " "
p "Are you ordering?"
are_you_ordering  = gets.chomp      

while are_you_ordering == "yes" 
    puts "We have Cocktails, Waters and beers for order."
    puts "What orders do you want to make?"
    customer_order = gets.chomp

    if customer_order == "cocktail"
        backlog_cocktails += 1 
        cocktail_profit = (cocktail_selling_price - cocktail_cost) * backlog_cocktails


    elsif customer_order == "water"
        backlog_waters += 1
        water_profit = (water_selling_price - water_cost) * backlog_waters



    else customer_order == "beer"
         backlog_beers += 1
        beer_profit = (beer_selling_price - beer_cost) * backlog_beers

    end
    p "We got cocktail: #{backlog_cocktails}, water: #{backlog_waters} and beer: #{backlog_beers} to make."
    puts "Do you want to make more order?"

    are_you_ordering = gets.chomp 

    total_ profit = cocktail_profit + water_profit + beer_profit
    p total_profit

end

Answer 1

之所以发生此错误，是因为您在计算nil时试图将其添加到当前total_profit的变量中。要解决此错误，请在cocktail_profit循环之前将water_profit，beer_profit和while初始化为0。

cocktail_profit = 0.0
water_profit = 0.0
beer_profit = 0.0

while are_you_ordering == "yes" 
    ...

调酒师Challange，错误代码：challange3.rb：64：in`<main>'：nil：NilClass的未定义方法'+'（NoMethodError）

1 个答案: