Ruby_Variables.md

Variables in ruby

There are 4 types of fundamental variables in ruby

1.-Global variables:

Global variables begin with $, Uninitialized instance variables have the value nil and produce warnings

$global_variable = 10
puts "Global variable is $global_variable"

2.-Instance Variables:

An instance variable has a name that begins with @ and its scope is limited to the object to which reference self

Two different objects, even when they belong to the same class, can have different values ​​in their instance variables

class Test

    	def set_example (n)

		@example = n

   	end

    	def set_example2 (n)

       	 @example2 = n

   	end

end

3.-Ruby Class Variables:

Class variables begin with @@ and must be initialized before they can be used in method definitions.

Referencing an uninitialized class variable produces an error. Class variables are shared among descendants of the class or module in which the class variables are defined.

Overriding class variables produce warnings

class Workers

    @@number_of_workers = 0

    def initialize (name, id)

	@cust_name = name
	@cust_id = id

    end

    def display_details()

    puts "Worker id #@cust_id"
    puts "Worker name #@cust_name"

    end


    def total_workers()

    @@number_of_workers += 1
    puts "Total is: #@@number_of_workers"

    end

end

4.-Ruby constants:

Constants begin with an uppercase letter. Constants defined within a class or module can be accessed from within that class or module, and those defined outside a class or module can be accessed globally.

class Example

    VAR1 = 100
    VAR2 = 200

    def show

       puts "Value of first Constant is #{VAR1}"
       puts "Value of second Constant is #{VAR2}"

    end

 end