A pointer is a valid C++ iterator. > but you trust it to optimize all that garbage away? Yep, if you learn about compilers you learn what kind of optimization

A pointer is a valid C++ iterator. > but you trust it to optimize all that garbage away? Yep, if you learn about compilers you learn what kind of optimizations are easy and hard for them to make. The kind that just flattens a few levels of nested definitions are easier.