Recall & Review
beginner
What is a doubly linked list?
A doubly linked list is a chain of nodes where each node has three parts: data, a pointer to the next node, and a pointer to the previous node. This allows moving forward and backward through the list.
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beginner
What steps are needed to insert a new node at the end of a doubly linked list?
1. Create a new node with the given data.<br>2. If the list is empty, make the new node the head.<br>3. Otherwise, traverse to the last node.<br>4. Set the last node's next pointer to the new node.<br>5. Set the new node's previous pointer to the last node.<br>6. Set the new node's next pointer to NULL.
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beginner
In C, what pointers does a node in a doubly linked list typically contain?
A node contains:<br>- A data field (e.g., int data)<br>- A pointer to the next node (struct Node* next)<br>- A pointer to the previous node (struct Node* prev)
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intermediate
Why do we need to update the previous pointer of the new node when inserting at the end?
Because the new node must know which node comes before it. Setting its previous pointer to the last node keeps the backward link intact, allowing traversal in reverse.
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intermediate
What happens if you forget to set the new node's next pointer to NULL when inserting at the end?
The new node might point to some random memory or garbage value, causing undefined behavior when traversing the list. It breaks the list's end marker.
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What is the first step when inserting a node at the end of a doubly linked list?
✗ Incorrect
You must first create the new node before linking it to the list.
If the doubly linked list is empty, what should the new node become?
✗ Incorrect
If the list is empty, the new node becomes the head (and tail) of the list.
Which pointer of the last node must be updated to link the new node at the end?
✗ Incorrect
The last node's next pointer should point to the new node.
What should the new node's next pointer be set to after insertion at the end?
✗ Incorrect
The new node is the last node, so its next pointer must be NULL.
Why is it important to update the new node's previous pointer?
✗ Incorrect
The previous pointer links the new node back to the node before it.
Explain the process of inserting a node at the end of a doubly linked list in your own words.
Think about how the new node connects forward and backward.
You got /6 concepts.
Describe the structure of a node in a doubly linked list and why each part is important.
Imagine walking through a chain in both directions.
You got /3 concepts.