When I wrote the following code, it runs normally:
class Application def initialize(name) @name = name end end class Email2 < Application end But when I changed Email2 to Email like this:
class Application def initialize(name) @name = name end end class Email < Application end I got the error message: superclass mismatch for class Email. Please help me.
The Email class must already be defined somewhere else.
You can test that by using the defined? method like this:
defined?(Email) Think about namespacing your code by using a module:
module MyNameSpace class MyClass end end Looks like you need to remove the definition from the CodeAcademy Context. Try deleting your browser cookies and refreshing the page.
Email class does not inherit from MessageThe error occurs because there's already a class Email defined somewhere else, that inherits from something else than Application.
When using the class keyword, if the class already exists ruby will try to reopen the class, allowing you to add things to the existing class definition.
If you write class Email < Application, ruby will try to make Email inherit from Application. Ruby classes can't have more than one parent class, so if the existing Email class already inherits from something else, you will get this error.
To inherit from Message, you write this: class Email < Message
