保护栏位是为了帮助防止外部程式码变更它的值，但可让衍生类别存取。

The field is protected to help prevent outside code from changing its value while allowing derived classes to access it.

youdao

保护栏位是为了帮助防止外部程式码变更它的值，但可让衍生类别存取。

The field is protected to help prevent outside code from changing its value while allowing derived classes to access it.

youdao