Linked Lists Overview

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Questions and Answers

What are the two main components of a linked list node?

Value and Pointer

Data and Address (correct)

Value and Index

Data and Key

What does the link component of a node in a linked list typically contain?

The index of the node

NULL or the address of the next node (correct)

The data type of the node

The value of the node

What value does the pointer head->link hold according to the linked list properties?

2000

2800 (correct)

In the linked list structure, what does the head represent?

The first node in the list Signup and view all the answers

What happens to the pointer current after the statement current = current->link; executes?

It points to the second node. Signup and view all the answers

Which of the following operations is NOT a basic operation of a linked list?

Sort the list Signup and view all the answers

How is memory managed for the nodes in a linked list?

Nodes are created dynamically during runtime Signup and view all the answers

What is the proper declaration to create a head pointer for a linked list node structure?

nodeType *head; Signup and view all the answers

What value does current->link->info represent after current points to the second node?

63 Signup and view all the answers

What should you NOT do to traverse a linked list using the head pointer?

Change the value of head during traversal. Signup and view all the answers

Which statement is true regarding a linked list with four nodes?

Every node points to NULL except the last node. Signup and view all the answers

What does the head pointer specifically contain within the context of a linked list?

The address of the first node. Signup and view all the answers

What data type is typically used for the link component in a linked list node structure?

nodeType* Signup and view all the answers

What would happen if a node's link component were incorrectly set to point to an invalid memory location?

The program would likely crash. Signup and view all the answers

What is required to successfully traverse a linked list?

A pointer to the first node. Signup and view all the answers

Which statement correctly describes the link structure of a linked list?

Links are unidirectional and point to the next node. Signup and view all the answers

What is the purpose of the statements 'newNode->link = q;' and 'p->link = newNode;' in the context of linked lists?

To insert a new node between two existing nodes Signup and view all the answers

What is the effect of changing the execution order of the insertion statements?

It does not affect the final outcome of the insertion Signup and view all the answers

What happens to the memory occupied by a deleted node after executing 'p->link = p->link->link;'?

It becomes dangling and inaccessible Signup and view all the answers

What is required to deallocate the memory of a deleted node in a linked list?

A pointer to the deleted node Signup and view all the answers

Which of the following statements correctly illustrates the deletion of a node with specific info from a linked list?

p->link = p->link->link; Signup and view all the answers

What happens to the first node if head is moved to the second node without saving a pointer to the first node?

The first node is lost, and cannot be accessed. Signup and view all the answers

Which statement accurately describes the process of traversing a linked list?

A separate pointer, such as current, is used to traverse the list. Signup and view all the answers

What is the result of executing the correct sequence of statements during node insertion?

The new node is inserted immediately after the specified node. Signup and view all the answers

What mistake occurs if the sequence of statements for inserting a new node is reversed?

The new node points back to itself and loses the rest of the list. Signup and view all the answers

Which pointer is essential to ensure safe traversal through a linked list?

A second pointer of the same node type. Signup and view all the answers

Why is it impractical to save a pointer to each node before advancing head?

It requires too much computer time and memory space. Signup and view all the answers

What does the code 'current = head;' accomplish in traversing a linked list?

It initializes the traversal at the head of the list. Signup and view all the answers

What does 'current = current->link;' do in the traversal loop?

It advances the pointer to the next node in the list. Signup and view all the answers

Study Notes

Linked Lists

A linked list is a collection of elements called nodes.
Each node (except the last) contains the address of the next node, called the link.
The address of the first node is stored in a separate location called the head.

Node Structure Definition

Each node is defined as a struct with data and link components.
The link component is a pointer to the next node.

Memory Locations Diagram

Example linked list with memory locations:
- Node 1: address 1200, data 45
- Node 2: address 1575, data 89
- The head pointer stores 1200, the address of the first node.

Linked List Properties

Example linked list:
- Head = 2000
- Head->info = 17
- Head->link = 2800
- Head->link->info = 92
To traverse the list, a temporary pointer "current" is created.
The statement "current = head" copies the value of head into current.
The statement "current = current->link" advances the current pointer to the next node.

Traversing a Linked List

The basic operations on a linked list are search, insert, and delete.
These operations require traversing the list.
A temporary pointer (e.g., current) is used to traverse the list, to avoid losing nodes.
The following code iterates through the list:

current = head;
while (current != NULL)
{
  // Process current node
  current = current->link;
}

Insertion

To insert a new node, newNode, after a node pointed to by p:
- Create the new node: newNode = new nodeType;
- Store data in the new node: newNode->info = 50;
- Set the new node's link to the next node: newNode->link = p->link;
- Set the original node's link to the new node: p->link = newNode;
The order of these statements is crucial. Reversing them can lead to the new node pointing to itself.

Insertion using two pointers

If q points to the node after p, the insertion process is simplified:
- Set the new node's link to q: newNode->link = q;
- Set the original node's link to the new node: p->link = newNode;

Deletion

To delete the node pointed to by p->link:
- Set p's link to the node after the one being deleted: p->link = p->link->link;
- This effectively removes the node from the linked list.
- However, the memory occupied by the deleted node remains allocated.
- To deallocate the memory, a pointer to the deleted node is needed.

Deletion Diagram

Example diagram illustrating the deletion of a node from a linked list.

Deletion Diagram with p->link = p->link->link

Example diagram showing the effect of the deletion statement p->link = p->link->link on a linked list.

Memory allocation

The memory for a list is obtained and freed dynamically using new and delete.
This dynamic allocation ensures that the program uses only as much memory as it needs for the list.

Key operations

Traversing a linked list is a fundamental operation for all other operations, including insertion and deletion.
Insertion and deletion involve manipulating node links to adjust the order of nodes in the list.
Using two pointers to simplify insertion code can improve efficiency.
Deleting a node effectively removes it from the list, but the memory it occupied remains allocated until explicitly deallocated.

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Description

This quiz covers the fundamentals of linked lists, including their structure, properties, and how to traverse them. Learn about nodes, pointers, and the overall data organization that linked lists provide. Perfect for students seeking to understand these essential data structures.