C++
From stack vs. heap to move semantics, templates, and the STL — a self-paced C++ track, beginner to advanced, built around real compilable examples.
Start here: the toolchain, the type/memory model, and the pointers underneath everything else in C++.
Who owns a piece of memory, when it dies, and how ownership moves without copying.
Inheritance, virtual dispatch, and the mechanics (and cost) of runtime polymorphism.
Templates, lambdas, and compile-time evaluation — the features that separate C++11-and-later from C-with-classes.
The standard library's containers and algorithms, and the classic data-structure/algorithm fundamentals underneath them.
Patterns, idioms, and the tooling that keeps a C++ codebase correct as it grows.