The article walks through a C programmer's journey from hard‑coded if‑else shape handling to embedding function pointers in structs, introducing shared function tables, automatic initialization, memory savings, inheritance via table overrides, and finally showing how C++ virtual functions automate the same mechanism.
This article explains C++ polymorphism, covering virtual functions, the override and final keywords, pure virtual functions, virtual destructors, vtable implementation, performance considerations, modern C++ improvements, and practical examples with code snippets.
This article walks through C++ object memory layout using concrete examples, covering basic data members, methods, private and static members, inheritance (with and without virtual functions), compiler optimizations, and address‑space layout randomization, all demonstrated with GDB inspections and code snippets.
Modern C++ performance suffers when seemingly harmless abstractions—such as virtual functions, hidden copies, non‑trivial destructors, overused std::shared_ptr, type‑erasing wrappers, std::variant/optional, and std::async—prevent inlining and efficient memory use, while patterns like std::move on returns, hidden destructors in tail recursion, and branchy loops thwart NRVO, tail‑call, and auto‑vectorization optimizations.
This article explains the purpose and proper use of C++'s virtual keyword, illustrating how virtual functions enable polymorphism, detailing class memory layout with vtables and vptrs, comparing performance impacts, and outlining when virtual functions and destructors are truly necessary.
This article explains how C++ compilers implement virtual functions using a hidden vptr and virtual table, showing how class size grows from 1 to 8 bytes, detailing memory layouts for single, multiple, and diamond inheritance, and providing commands to dump vtable and layout information.
