What does the operator--() do in a doubly linked list iterator?

• A. It moves the iterator to the previous node.
• B. It moves the iterator to the next node.
• C. It resets the iterator to the head.
• D. It returns the data at the current node.

Answer: (A)

In a doubly linked list, you can move in both directions because each node has pointers to both its successor and its predecessor. The decrement operator on an iterator moves you backward, so applying it updates the iterator to point to the node that comes before the current one—the previous node. This is the opposite of the increment operator, which moves you forward to the next node. Dereferencing the iterator gives you the data at the current node, not the act of moving. Resetting to the head or returning data are not what the decrement operator does. If you’re considering pre- versus post-decrement, pre-decrement returns the updated position after moving backward, while post-decrement would yield the original position before the move.