Class VS Struct

1、在语言层面：class的default member访问方式和继承方式为private，struct的default member访问方式和继承方式为public。

2、Struct：

　　small passive objects that carry public data and have no or few basic member function.

　　Data Contain

　Class: Bigger active objects that carry private data, interfaced through public function

　　　　Complex Data structure

Summary:

　　// 1.Use struct for passive objects with public data, use class for active objects with private data.

　   // 2.Use setter/getter to access class's data

　 // 3. Avoid making setter/getter if possible.