1. How grep recursively searches a directory for the desired string.
2. Determine whether the binary tree is symmetric.
3. C++ virtual table
4. The difference between epoll and select
5.mysql index, transaction, isolation level
6. How to deal with ambiguity in multiple inheritance in c++ if two base classes have member functions/variables with the same name. Is it possible to set all member functions as virtual in c++, what will be the problem.
7.md5sum sort cut and so on shell commands.
8. Multi-threaded programming, access/modification of critical resources.
9. What should I do if there is insufficient memory when using functions such as new malloc?
10. The difference between http and https.
11. Interprocess communication.
12. Thread shared resources, private resources.