Barry Revzin has a talk explaining about different kinds of iterator. The C++ iterator is a maximalist, very powerful and flexible idea which - as a result - also has lots of opportunities to set everything on fire. Their model was the C pointer, we can iterate a pointer, compare it against some sentinel "end" value, dereference it, but also we could index into it, decrement the pointer and go backwards, comparing against a "start" value, and we can write to a reference rather than just read from it.

This is far more than most iterator designs allow, and as I said if you needed more this is very welcome, but if you didn't it's probably bad news.

C++ can sort iterators for example, so long as they're suitable for indexing back and forth as the sort progresses. Rust's sort functions are defined on its slice types, which makes sense in practical terms but if what you've got isn't quite a slice but could meet the requirements in C++ that's a problem for you.