You copy a singly linked list into a doubly linked list by iterating over the singly linked list and, for each element, calling the doubly linked list insert function.

It is easier to insert into a singly linked list.

A list is an abstract data structure, usually defined as an ordered collection of data. A linked list refers to a specific implementation of a list in which each element in the list is connected (linked) to the next element.

Linked list of strings, for example.

A doubly linked list allows traversal in both directions (forward and backward) by having each node point to both its next and previous nodes. A circular linked list is a type of linked list where the last node points back to the first node, forming a circular structure. This allows continuous traversal through the elements without a definitive end.