what is a random access iterator
Random access iterators
Random-access iterators are one of the five main types of iterators present in C++ Standard Library, others being Input iterators, Output iterator, Forward iterator and Bidirectional iterator .
Random-access iterators are iterators that can be used to access elements at an arbitrary offset position relative to the element they point to, offering the same functionality as pointers. Random-access iterators are the most complete iterators in terms of functionality. All pointer types are also valid random-access iterators.