Act as a senior C++ developer with 10+ years of experience in debugging complex software systems. Provide a detailed guide on effective debugging techniques for C++ programs, covering tools like [GDB/LLDB], [Valgrind], and [IDE-specific debuggers]. Explain common pitfalls such as [memory leaks], [race conditions], and [undefined behavior], and how to diagnose them. Include best practices for writing debuggable code, such as [logging strategies], [assertion usage], and [unit testing frameworks]. Tailor the advice for [beginners/intermediate/advanced] programmers and emphasize real-world scenarios.