1. The first configuration is configured to order the parent class, then the class constructor, destructor sequence is first class destructor, then the parent class destructor
2. Be sure to declare, otherwise the use of a pointer to the parent class subclass object, it does not call the destructor subclasses.
3. Polymorphism is the parent class pointer pointing subclass, the subclass then calls virtual function override.
4. vtable
5 and 6 questions slightly difficult questions
Heap sort is also important.
Processes, threads, coroutines
The concept of thread synchronization
message queue
Shared memory
Network protocol, epoll, select