Resources: https://www.youtube.com/watch?v=Fv8oj8EdssY https://www.youtube.com/watch?v=F9eDv-YIOQ0 https://www.internalpointers.com/post/writing-custom-iterators-modern-cpp https://learn.microsoft.com/en-us/cpp/standard-library/iterator?view=msvc-170 https://stackoverflow.com/questions/8054273/how-to-implement-an-stl-style-iterator-and-avoid-common-pitfalls https://www.boost.org/doc/libs/latest/libs/iterator/doc/iterator_facade.html