Up shape (upcast)

In simple words, the upward shape refers to viewing the subclass object as a parent class object. Let's take a look at it as follows:

Set: Student inherited from person
Then:
Student person
Student * person *
Student & person &

Internal principle:
A subclass object has a majority of members of a parent class object, except the Private Members of the parent class.
For example, if we say that Zhang San is a student, then we can regard Zhang San as a Chinese student. we can treat the sub-class Object Zhang San as the parent class Object of the Chinese people, which forms an upward shape. However, you can't say that Zhang San is a Chinese, but must he be a student? Obviously not necessarily.

Class person {};
Class student: public person {};

Person Chinese;
Student zhangsan;

Student * Stu = & Chinese;
Student & stud = Stu;

 

Up shape (upcast)