1、三种继承方式：公有继承，私有继承，保护继承。
https://blog.csdn.net/let_life_stop/article/details/80933661
2、基类和派生类
https://www.cnblogs.com/HenryWEI/p/9663629.html
深入学习：https://blog.csdn.net/redrainy/article/details/1552252
3、面向对象三要素：封装，继承，多态
https://www.cnblogs.com/dej-11/archive/2017/11/15/7837995.html
https://blog.csdn.net/jianyuerensheng/article/details/51602015