CS2470: Systems Programming in C/C++ - Semester Summary #

Course Overview #

This semester, we’ve explored systems programming through the lens of C and C++, focusing on how programs interact with hardware and operating systems. We’ve built a foundation for understanding how software works at a lower level than most application programming.

Key Topics Covered #

C Programming Fundamentals #

• Basic C Syntax: Functions, variables, control flow
• Memory Management: Stack vs. heap allocation
• Pointers and Arrays: Pointer arithmetic, array manipulation
• Data Structures: Implementing linked lists, structs
• Memory Layout: Understanding how programs are organized in memory

Systems Concepts #

• File I/O:
  • High-level file operations (fopen, fread, fgets)
  • Low-level system calls (open, read, write)
• Process Management:
  • Process creation with fork()
  • Program execution with exec()
  • Process synchronization with wait()
• Interprocess Communication:
  • Pipes for communication between processes
  • Redirecting standard input/output
• Memory Mapping: Using mmap for shared memory between processes

Data Representation #

• Primitive Types: Sizes and representations of int, char, etc.
• Endianness: Little vs. big endian representation
• Structs and Memory Layout: Padding, alignment
• Slices: Non-owning views into memory

Tools and Techniques #

• Compilation Process: From source to executable
• Makefiles: Automating the build process
• Debugging with GDB: Setting breakpoints, inspecting memory
• Memory Safety: Avoiding leaks, buffer overflows

Advanced Topics #

• Introduction to C++: Classes, templates, standard library
• Smart Pointers: Managing memory with unique_ptr and shared_ptr
• Network Programming: TCP sockets and client implementation
• Shell Programming: Building a command interpreter

Major Projects and Examples #

Throughout the semester, we implemented several significant programs:

1. Basic Data Structures:

   • Linked lists with various operations
   • Dynamic arrays

2. Text Processing Tools:

   • Word counting and text analysis
   • File slicing and manipulation

3. Calculator:

   • Tokenizing input
   • Parsing expressions into abstract syntax trees
   • Evaluating expressions

4. Shell Interpreter:

   • Command parsing and execution
   • Process management
   • I/O redirection and pipes

5. Network Client:

   • TCP socket programming
   • HTTP client implementation

Key Takeaways #

Understanding the Stack and Heap #

• Stack: Automatic memory management for local variables
• Heap: Dynamic memory allocation with malloc/free
• Memory Ownership: Responsibility for freeing allocated memory

The Process Model #

• Processes as isolated units of execution
• The fork/exec pattern for process creation
• File descriptors and the Unix I/O model

C vs. Higher-Level Languages #

• Direct memory manipulation
• No automatic memory management
• Close relationship to the underlying hardware

Systems Programming Patterns #

• Resource acquisition and release
• Error checking and handling
• Defensive programming techniques

Looking Forward #

The skills you’ve learned in this course provide a foundation for:

• Operating systems development
• Embedded systems programming
• Performance-critical applications
• Understanding how higher-level languages work under the hood
• Systems-level debugging and optimization

Final Thoughts #

Systems programming requires attention to detail and a deep understanding of how computers work at a fundamental level. The C language, despite its age, remains essential for systems programming due to its efficiency and direct access to hardware resources.

As you continue your computer science journey, the knowledge gained in this course will help you understand the tradeoffs between abstraction and performance, and give you the tools to work at different levels of the software stack when needed.

Remember that good systems programming is not just about making things work, but making them work efficiently, reliably, and securely.