struct Student { int id; int age; };

struct Student s1; struct Student *p = &s1; 将指针指向结构体 跟正常的指针区别不大，只是类型换成了结构体

通过结构体变量访问成员 struct Student s1; s1.id = 1001; s1.age = 19;

通过结构体指针访问成员 struct Student *p = &s1; p->age; (*p).age;