使用自定义的类。

Use custom class.

youdao

类似地，对于自定义的类，必须使得编译器可以访问和类相关的定义。

Similarly, for our own classes, we must make the definitions associated with the class available to the compiler.

youdao

自定义的类构造器应该调用父类的构造器方法，做除这之外的任何事情是指定到你的类。

Your class constructor should invoke the constructor method for the parent class, in addition to anything it does that is specific to your class.

youdao