undefined method 'rectangle' for main

Question

错误信息是：
undefined method 'rectangle' for main:object(NoMethod Error)
这个是ruby的错误提示，不知道是意思，请大神帮忙解决
代码如下：
class Rectangle
def initialize(wdth,hgt)
@width = wdth
@height = hgt
end
def width=(wdth)
@width = wdth
end
end

r = Rectangle(2,3)
puts r.width = 5
puts r.width

Answer 1

应该是：

 r = Rectangle.new(2,3)