About class variable question?

[Zhao Yi]

Please see this code below. It will get "can't convert nil to string
error". Why can't the @name be assigned? I have set the @name = "world".

class Hello
@name="world"
def say
puts "Hello "+@name
end
end
h=Hello.new
h.say

 

[Stefano Crocco]

Please see this code below. It will get "can't convert nil to string
error". Why can't the @name be assigned? I have set the @name = "world".

class Hello
@name="world"
def say
puts "Hello "+@name
end
end
h=Hello.new
h.say

@name is an instance variable of the Hello object, not of instances of Hello,
such as h. To create an instance variable of instances of Hello, you need to
assign it a value in an instance method. Usually, this is done in the
initialize method:

class Hello

def initialize
@name = "Hello"
end

def say
puts "Hello" + @name
end

end

h = Hello.new
h.say

I hope this helps

Stefano