What is difference between these two methods in Ruby?

Question

What is difference between these two methods in Ruby?

class Mod   

      def doc(str)
          ...
      end

      def Mod::doc(aClass) 
          ...
      end
end

Answer 1

Mod::doc()

is a class method, whereas

doc()

is an instance method. Here's an example of how to use both:

class Mod   
    def doc()
        puts 1
    end

    def Mod::doc() 
        puts 2
    end
end

a = Mod.new
a.doc   #=> 1
Mod.doc #=> 2

Here's a question that compares it with

self.doc()