Question

我正在创建一个非常简单的“存储库”作为我的第一个真正的ruby脚本。我创建了人们可以创建项目和起始值的部分，但我似乎无法确定如何使人们不能递增（或递减）0或负数。

我要添加的代码如下：

class Item
 attr_accessor :name, :count
 def initialize (name,initCount )
 @name=name.downcase
 @count=initCount
end

def add(amount)
@count += amount
end

def sub(amount)
@count -= amount
end

end

def prompt()
puts @items.inspect
puts " (A)dd item\n (R)emove item\n (L)ist items\n (I)ncrease item\n (D)ecrease items\n (Q)uit "
select = [(print '?: '), gets.rstrip][1]


if (select.upcase=="A") then
puts "Add Item\nItem name"
name=[(print 'Name? : '), gets.rstrip][1]
puts "Initial Count"
count= [(print 'Count? : '), gets.rstrip][1]
@items.push(Item.new(name,count.to_i)) unless @items.index(@items.find { |l| l.name == name })

end

感谢任何帮助。

Answer 1

考虑像这样组织你的代码。我可能犯了一些错误，但你会明白这一点。

PROMPT_TEXT =
" (A)dd item
 (R)emove item
 (L)ist items
 (I)ncrease items
 (D)ecrease items
 (Q)uit ?: "

ILLEGAL_PROMPT_RESPONSE_MSG =
  "You can't enter that! What were you thinking??"
NEGATIVE_NUMBER_MSG =
  "If I've told you once, I've told you a thousand times: NO NEGATIVE NUMBERS!"
NOT_NUMBER_MSG =
  "If that's a number, it must be Roman, and they aren't allowed."
TRY_AGAIN_MSG = "Try again...

。

def prompt()
  loop do
    puts @items.inspect # What's this?
    puts PROMPT_TEXT
    gets.rstrip.upcase case
      when "A"
        break if add_item
      when "R"
        ...
      when "L"
        ...
      ...
      when "Q" then return
      else
        puts ILLEGAL_PROMPT_RESPONSE_MSG
      end
    puts TRY_AGAIN_MSG
  end
end

def add_item
  puts "Add Item\nItem name"
  print 'Name? : '
  name = gets.rstrip
  puts "Initial Count"
  print 'Count? : '
  count = gets.rstrip
  unless count =~ /\d+/
    if count =~ /-\s*\d+/
      puts NEGATIVE_NUMBER_MSG
    else
      puts NOT_NUMBER_MSG
    end
    return false
  end
  @items.push...
  true
end

旁白：陈述

name=[(print 'Name? : '), gets.rstrip][1]

让人想起一个以“abomin”开头并以“ation”结尾的单词。： - ）

Answer 2

class Item
    attr_accessor :name, :count
    def initialize (name,initCount )
        raise if initCount<0

        @name=name.downcase
        @count=initCount
    end

    def add(amount)
        raise if amount<0

        @count += amount
    end

    def sub(amount)
        raise if amount<0 || amount>@count

        @count -= amount
    end

end

创建广告资源时，如何阻止人们添加负数？

2 个答案: