Dynamic Data Structures in C: Linked Lists Quiz Quiz

Challenge your understanding of dynamic data structures in C with this focused quiz on linked lists. Explore key concepts, implementation scenarios, memory management, and pointer manipulation relevant to linked list operations in C programming.

1. Understanding Node Structure

   In a singly linked list implemented in C, which member is most commonly used to point to the next node in the list?

   1. next
   2. left
   3. last
   4. tail

   Explanation: The 'next' member commonly points to the following node in a singly linked list, allowing traversal from one node to the next. 'Left' is a distractor often seen in binary trees, not singly linked lists. 'Tail' typically refers to the last node itself and is not a pointer in the node struct. 'Last' is not a standard member in C linked list node definitions.

2. Memory Allocation

   What is the correct function to allocate memory for a new node in a C linked list?

   1. assign
   2. memory
   3. allocate
   4. malloc

   Explanation: The 'malloc' function is used in C to allocate dynamic memory on the heap, which is essential for creating new nodes at runtime. 'Allocate', 'assign', and 'memory' are not valid functions in the C standard library for memory allocation. Choosing the wrong function or a non-existent one would cause compilation errors or undefined behavior.

3. Node Insertion

   When inserting a new node at the beginning of a singly linked list, which step must be performed first?

   1. Free the previous head node
   2. Set the new node's next pointer to the current head
   3. Set the current head's next to the new node
   4. Update the head to point to the new node

   Explanation: You must first set the new node’s next pointer to refer to the current head so it links properly into the existing list. Updating the head before linking would sever the connection to the rest of the list. Setting the current head’s next to the new node is incorrect for a head insertion scenario. Freeing the head node at this point would lead to loss of data and potential errors.

4. Handling Empty Lists

   If the head pointer of a linked list in C is NULL, what does this signify about the state of the list?

   1. The list is full
   2. The list has one element
   3. The list is empty
   4. The list contains garbage values

   Explanation: A head pointer set to NULL indicates that there are no elements in the list, meaning it is empty. If the list had one element, the head would point to a valid node. Dynamic lists in C are not considered 'full' since they grow as needed with memory. 'Garbage values' is misleading, as NULL is a defined, safe value for the head in this case.

5. Deleting Nodes

   When deleting a middle node from a singly linked list in C, which pointer must be updated to maintain the integrity of the list?

   1. The deleted node's next pointer
   2. The deleted node's data pointer
   3. The previous node's next pointer
   4. The next node's previous pointer

   Explanation: To remove a middle node, the previous node’s next pointer must bypass the node being deleted and point to the subsequent node. Adjusting only the deleted node's next pointer does not change the list structure. There is no 'data pointer' standard in linked lists. The next node's previous pointer applies to doubly linked lists, not singly linked ones.