Reversing a singly linked list means inverting the direction of every link rather than permuting the data between nodes — each node's next field is redirected to its predecessor, the original head's link becomes null, and the head reference is finally reassigned to the original tail. The iterative method carries a three-pointer window (previous, current, next) through a single forward pass, where the next pointer exists solely to preserve the forward reference before the link that supplies it is overwritten; without it the remainder of the list becomes unreachable. This belongs to data structures and pointer manipulation, running in O(n) time with O(1) auxiliary space, and stands as the canonical in-place structural transformation of a linked sequence.
Reversing a singly linked list means inverting the direction of every link rather than permuting the data between nodes — each node's next field is redirected to its predecessor, the original head's …