如果您想为一个类的所有实例维持一个变量的实例，将会用到静态类成员变量。

If you want to maintain a single instance of a variable for all instances of a class, you will use static-class member variables to do it.

youdao

我把数字变成是Classifier 2类中的成员变量，这将允许我避免将其作为参数传递给一大堆静态方法。

I've made the number a member variable within the Classifier2 class, which allows me to avoid passing it around as a parameter to a bunch of static methods.

youdao

你回答你的问题基本。静态变量（一个函数或者类的成员变量或局部变量）是只初始化一次，终止。例如；

So as you see although we call foo function three times the initialization of a static varible is done only once.

youdao