Reusable code, reusable data structures

DRY -- don't repeat yourself -- is an important software engineering principle. Repetitive code is error-prone code. Inevitably, and sooner rather than later, we will forget to change one of these repetitive code locations. C++ offers many different tools to share code and data and I often see novice and intermediate programmers struggle with choosing the best one in each situation. We have template functions, template classes, std::variant, virtual classes and std::any. We have some common associated programming patterns like CRTP, templated base classes, template functions taking function arguments. All of these have their uses and in my talk, I want to develop some intuitions on when to use which.