Listing 11 sets this as a class constant.

清单11将其设置为类常量。

youdao

You declare a class constant with the const keyword.

用const关键字声明类常量。

youdao

Like its global cousin, a class constant is immutable once defined.

与全局属性一样，类常量一旦定义就不可更改。

youdao

A limited class of problems is one in which the acceleration is just a constant.

在这类有限的问题里,加速度均为常数

耶鲁公开课 - 基础物理课程节选

So, yes, class of 2011, change will be a constant in your lives.

WHITEHOUSE: President Obama Delivers Commencement Address at Miami Dade College | The White House

And Hancock and his descendants served as a constant source of conversation between my father and me, a vital link between us when, class-wise, and in every other wise, each year placed us farther apart.

NEWYORKER: Dead Man Laughing