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class variables


Overview

Class variables begin with @@ and can be shared between modules.

In this example the variables formatted with @ (instance variables) are unique per method, but variables formatted with @@ (class variables) can be remembered and added upon between methods.

Code

#!/usr/bin/ruby

class Customer
   @@no_of_customers=0
   def initialize(id, name, addr)
      @cust_id=id
      @cust_name=name
      @cust_addr=addr
   end
   def display_details()
      puts "Customer id #@cust_id"
      puts "Customer name #@cust_name"
      puts "Customer address #@cust_addr"
    end
    def total_no_of_customers()
       @@no_of_customers += 1
       puts "Total number of customers: #@@no_of_customers"
    end
end

# Create Objects
cust1=Customer.new("1", "John", "Wisdom Apartments, Ludhiya")
cust2=Customer.new("2", "Poul", "New Empire road, Khandala")

# Call Methods
cust1.total_no_of_customers()
cust1.display_details()
puts "---"
cust2.total_no_of_customers()
cust2.display_details()


Output

Total number of customers: 1
Customer id 1
Customer name John
Customer address Wisdom Apartments, Ludhiya
---
Total number of customers: 2
Customer id 2
Customer name Poul
Customer address New Empire road, Khandala


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