C++ Study Questions#

What are some common examples of undefined behavior?
- What is memory corruption?
  - What are some common causes of it?
- How can you get UB without memory corruption?
- How does UB interact with optimization?
What is RAII? How does it differ from garbage collection?
Why use smart pointers instead of raw pointers?
What is the STL?
- What is it useful for?
- What are some common STL collections?
- What are some common STL algorithms?
- How do iterators work?
- Why can’t you dereference the end iterator?
What is the difference between “value semantics” and “reference semantics”?
What is “type erasure”?
- How is std::function implemented?
- How is std::any implemented?
  - What does std::any even do?
Why does an empty struct have a size of 1 and not 0?
What is std::atomic?
- How does it differ from volatile?
- How can it be optimized?
What are the versions of the C++ standard?
- What major features were added in each of them?
What are the major C++ compilers?
- Under what licensing terms are they available?

C++ Performance#

What are some common compiler optimizations?
- What are some optimizations a compiler cannot do?
- What are downsides to having the compiler do optimizations?
Why are virtual function calls slower?
What parts of a codebase need most optimizing?
- What parts do not?
Common compiler flags
- What is the difference between -O2, -O3 and -Os?
- What is -g?
  - Why is it normally combined with -O0?
    - What does -O0 do?
    - How is that different from what -g does?
What is the difference between throughput and latency?

Operating System Questions#

What is the difference between the stack and the heap?
What is an operating system kernel?
- What are some examples of operating system kernels?
- What is “kernel” or “supervisor” mode?
- What is a monolithic kernel vs a microkernel?
- What is a driver?
  - Can they run in usermode?
    - When?
What is a system call?
- What is the difference between a blocking and non-blocking system call?
What is the difference between a process and a thread?
- What are the performance implications?
Describe different forms of IPC
- What is the difference between brokered and non-brokered IPC?
- What considerations should you take into account when choosing an IPC system?
Describe virtual memory.
- What is an address space?
- What is memory protection?
- What is paging?
  - What is a page fault?
- What does a kernel have to do to implement virtual memory?
- How does a program allocate more memory on the stack?
- How does a program allocate more memory on the heap?
  - In userspace?
  - What syscalls might it have to make?
- How do memory mapped files work?
  - When should you prefer this to read and write syscalls?
- How does shared memory work?
  - When should you prefer this to other forms of IPC?
- What is swap?
- What is a TLB?
  - What performance implications does it have?

Network Study Questions#

Explain the layers of the OSI model
- How do they map to Internet-based protocols?
Explain IP basics
- What is IP?
- What is an IP address?
  - What is a subnet?
  - What is a non-routable IP address?
  - What is localhost?
    - When would we use it?
  - What is NAT?
    - When is it used?
- How does IP relate to link-level protocols?
  - Give some examples of link-level protocols.
  - Explain CSMA/CD.
  - What is MTU?
  - Explain Path MTU Discovery, and why it’s important.
- What is ICMP?
  - What are 2 command-line utilities that use it?
  - Why is it important?
- What is the difference between a hub, a switch, and a router?
- What is the difference between IPv4 and IPv6?
Explain DNS basics
- What is DNS?
- What are some types of DNS records?
- On Unix
  - What is /etc/hosts?
  - What is /etc/resolv.conf?
  - What sort of things can go wrong if these are configured incorrectly?
- How do you access DNS from your applications?
What is a VPN?
Explain the basics of TCP.
- How does TCP implement reliability on top of IP?
- TCP is stream-oriented, UDP is packet-oriented. What does this mean?
- Explain the TCP three-way handshake.
  - What are SYN cookies?
- How do TCP acknowledgements work?
  - How does TCP handle the lack of negative acknowledgements?
- What is the TCP window size?
Explain the basics of UDP.
- What are some differences between TCP and UDP?
- Why might you want to use UDP?
- How are UDP broadcasts implemented?
On Linux, what sort of things can you tune about networking using sysctl?
- Why might you want to do this?
Why are heartbeats important?
- Why might they be implemented in user protocols?
  - Why is TCP keepalive not enough?

Network Programming Practice Projects#

Echo server
- Can test by hand using netcat
- v1: Accepts single TCP connection, echos all inputs
- v2: Use threading to accept multiple connections, echo each to itself
- v3: Use single-thread
  - select or epoll syscall
  - async in Rust
  - Network reactor/dispatcher library in C++
Chat server
- Accept multiple connections
- Can test by hand using netcat
- v1: Send all whole lines (requires buffering) to all clients
  - No length restriction
- v2: Handshake to set username
  - Make still it still is testable using netcat
  - Server sends username along with messages
File server
- Simple HTTP-like protocol to specify filename of what file to send
  - Make sure you sanitize for inputs!
- v1: Serve one static file at a time
- v2: Stream multiple files to multiple clients without using threads
- v3: Support uploads
  - Write custom client
Exchange
- v1: Just exchange connection
  - Keep order books
    - When new order comes in compatible with old order, make trade
    - One security at first, then multiple
      - But build multiple into protocol right away
  - TCP Protocol:
    - Create a custom protocol with CLI client
    - Client -> Server
      - Orders
        
        Only GTC limit orders at first
        
        Quantity
        
        Security
        
        Price
        
        Buy/Sell
        
        Order ID
        
        Why is this useful?
    - Server -> Client
      - Order confirmation
        
        All order information, echoed
      - Trade confirmation (when orders match)
        
        Also indicate whether client was maker or taker
- Add-ons
  - Add heartbeats to protocol
  - Market data
    - UDP broadcast
    - Current state of order books
  - Drop copy
    - Separate TCP records of all trades
    - Record trades in file before confirming
    - Allow replay of previous days’ trades
  - Fees and kickbacks
    - Charge takers
    - Reimburse makers
    - Configurable on by-security basis
  - Credit limits
  - Advanced order types
    - IOC/FOK
    - Maker-only orders
  - FX-style last look
  - SSL support

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C++ Network Programming: Study Questions and Practice Projects

C++ Study Questions#

C++ Performance#

Operating System Questions#

Network Study Questions#

Network Programming Practice Projects#

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