Ruby类中的未定义方法错误[关闭]

Question

我正在尝试为橘子树编写一个简单的类...但出现此错误：pine_orangetree.rb:11:in oneYearPasses': undefined method+' for nil:NilClass (NoMethodError)

当我调用 oneYearPasses 方法时...为什么会这样？

class OrangeTree

    def initalize
        @height = 0
        @oranges = 0
    end



    def oneYearPasses
        @height += 2
        @oranges = 0

        if @height > 7
            @oranges += 10
        end

        if @height < 30
            puts "Another year has passed..."   
        else
            puts "The orange tree died..."
        end     
    end

    def height
        puts "The tree is #{@height} inches tall."
    end

    def countTheOranges
        puts "There are #{@oranges} on the tree."
    end

    def pickAnOrange
        @oranges -= 1
        puts "You picked an orange."
        puts "There are #{@oranges} left."
    end


end

tree1 = OrangeTree.new
tree1.oneYearPasses
tree1.height

Answer 1

initalize 这个词有错别字。应该是initialize。

并且由于拼写错误，在创建对象时不会调用initalize 方法，因此在创建时未定义实例变量@height。并且您不能在尚不存在的对象上调用 +=。

另外作为旁注，您不应该突然添加太多空白行。这违反了Ruby Style Guide。