Positional insertion into a singly linked list requires reaching the predecessor at position n−1 and rewiring two references in a strictly ordered sequence: the new node's next field must first be set to the predecessor's successor, and only then may the predecessor's next field be redirected to the new node — reversing this order severs the remainder of the list. Because only forward traversal is available, locating the predecessor costs O(n) while the rewiring itself is O(1), and insertion at the head is a distinct case in which the head pointer, not a predecessor's link field, is the reference being updated. The lesson situates this within data structures and the C/C++ memory model, distinguishing heap-allocated nodes reachable only through pointers from stack-resident local pointers and the globally scoped head that constitutes the list's identity.
Positional insertion into a singly linked list requires reaching the predecessor at position n−1 and rewiring two references in a strictly ordered sequence: the new node's next field must first be se…