Ruby Variable Scope

ruby_variable_scope.rb

# Global
  class Scope
    $global = "I am a global variable"
    @@class_variable = "I am a class variable"
    
    def initialize(instance_variable) 
      @instance_variable = instance_variable
    end
    
    def instance_message
      @instance_variable
    end
    
    def self.class_message
      @@class_variable
    end
  end

# Creating a new instance of the Scope class called example
example = Scope.new("I am an instance variable")  
# $global is a global variable so it can be called anywhere
puts $global

# example is a instance of the Scope class. We set the input "I am an instance variable" to the instance variable
# @instance_variable in the initialize method. We then put @instance_variable into a method called instance_message.
puts example.instance_message

# @@clasS_message is a class variable which means it is accessable to the entire class. Notice we also had to
# create a class method with self.class_message as it is not an instance method like instance_message
puts Scope.class_message
# Returns
"I am a global variable"
"I am an instance variable"
"I am a class variable"