Comments are a useful tool to give contextual information directly in the source code. They are most typically used as a clarification comments and documentation comments (top Google result for code comments). However, there is a third use which I found comments to be useful for, documenting history!
constexpr variables are a powerful feature of C++. They have the potential to improve runtime performance and also convert some runtime errors to compile time errors. However, they are sparely used in code bases due to the constraints they impose on the developer. This post will argue that their use, especially in the context of templating should be considered more often.