Technically, OOP is just about abstract data typing, inheritance, and polymorphism, but other issues can be at least as important. This section will cover these issues.

• 从技术上来说,面向对象仅仅是指抽象数据类型、继承和多态,但是还有一些问题也行挺重要的,这一节将对这些问题进行讨论。