如何在swift 2.0（iOS）中的单例类中创建可全局访问的结构数据？

I'm very new to iOS programming and swift. I am trying to create a singleton class to store my global data. My global data are a struct and an array of this struct. I want to have only one instance of this class, thus a singleton class. Global data should be accessible and editable to all ViewControllers. I have been searching around and I almost have it figured out except one last part. Here is the singleton class:I'm very new to iOS programming and swift. I am