ruby学习--varaible

 #全局变量
 $global_variable=10
 class Class1
     def print_global()
         puts "Global variable in Class1 is #{$global_variable}"
     end
 end
 class1obj=Class1.new
 class1obj.print_global()

 #实例变量
 class Customer
     def initialize(id,name,addr)
         @cust_id=id
         @cust_name=name
         @cust_addr=addr
     end
     def display_detalis
         puts "Customer id #{@cust_id}"
         puts "Customer name #{@cust_name}"
         puts "Customer addr #{@cust_addr}"
     end
 end
 cust1=Customer.new("","John","Wisdom")
 cust1.display_detalis

 #类变量
 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 addr #{@cust_addr}"
     end
     def total_no_of_customers()
         @@no_of_customers +=1
         puts "Totla number of customers:#{@@no_of_customers}"
     end
 end
 cust1=Customer.new("","John","Wisdom")
 cust2=Customer.new("","Poul","New")

 cust1.total_no_of_customers
 cust2.total_no_of_customers