Jawaharlal Nehru Technological University Hyderabad B.Tech II Year DATA STRUCTURES Previous Question Paper (October - 2020 - R15)

A Circular Linked List is a variation of a linked list where the last node points back to the first node instead of NULL, creating a continuous loop. This allows for traversal of the entire list starting from any node. An example is a round-robin task scheduler where processes are cycled through repeatedly.

A Doubly Linked List contains nodes where each node has two pointers: one to the next node and one to the previous node. This structure allows bidirectional traversal. An example is the 'Undo' functionality in a text editor, where navigating back and forth through states is required.

The following C function deletes the first occurrence of a specified integer from a singly linked list:

void deleteNode(struct Node** head, int key) {
    struct Node *temp = *head, *prev;
    if (temp != NULL && temp->data == key) {
        *head = temp->next;
        free(temp);
        return;
    }
    while (temp != NULL && temp->data != key) {
        prev = temp;
        temp = temp->next;
    }
    if (temp == NULL) return;
    prev->next = temp->next;
    free(temp);
}

The function handles three cases: deleting the head node, deleting a node in the middle or end, and handling cases where the element is not found.