Of course a basic iteration between begin()/end() will never contain out of range elements, but neither will valid increment between two integers. No need for iterators in that case either.
Say I want to do something fancy, like getting element number 11 from an array.
With an integer index I can pass 11, with random access iterators I can use begin() + 11.
Now my array only has five elements. So I check.
11 < 5? Comparison valid, successfully avoided a crash.
begin() + 11 < end() ? How where the rules for pointer comparison again, something about within an allocation and one past the end?
> something about within an allocation and one past the end?
Yeah, I forgot about that. So I agree there is some subtly which is likely to catch beginners.
Your example could safely be:
if (std::distance(begin, end) > 5)
Another approach I would recommend is to write a `guarded_advance` which takes an integer and the end pointer.
Also note that the situation you are describing is still a little unusual because the baseline assumption is it takes linear time to advance an iterator by more than 1 increment.
> but neither will valid increment between two integers. No need for iterators in that case either.
The purpose of an iterator is to abstract data structure access. The coordinate inside a complex data structure may not be representable by an integer.
What behavior is undefined in incrementing a pointer between a begin and end range?