I have a Macbook and I have an iPad. Comparing with other similar products I have such as an IBM ThinkPad and a Samsung Galaxy device you cannot avoid the feeling of apple infinite aspiration to reach the highest quality possible. This core value is one of apple’s greatest contributions. The spirit of Steve Jobs will remain with us for ever.
The Visitor Design Pattern
The visitor design pattern allows us to add operations to objects that already exist without modifying their classes and without extending them.