Linked lists are linear data structures where each element (called nodes) consists of data and a pointer to the next node. Nodes are dynamically allocated in memory. There are three types of linked lists: singly linked, doubly linked, and circular linked. Singly linked lists contain nodes with a data field and next pointer, with the last node pointing to null. Basic operations on linked lists include creating, inserting, deleting, searching, and reversing nodes. Doubly linked lists add a previous pointer to each node for bidirectional traversal. Circular linked lists connect the last and first nodes to form a loop.
1. BIRLA INSTITUTE OF TECHNOLOGY MESRA,
JAIPUR CAMPUS
NAME :- NIKHIL AGRAWAL
ROLL NO :- MCA/25004/18
TOPIC:-LINKED LIST
2. Linked List
It is a linear collection of data elements, called nodes, where the linear
order is implemented by means of pointers.
Nodes are structures made up of data and a pointer to another node.
Usually the pointer is called next.
3. NODE
Each Node of a list is comprising of two items -
the data and a reference to the next node.
The last node has a reference to null. The entry
point into a linked list is called the head of the
list.
It should be noted that head is not a separate
node, but the reference to the first node.
If the list is empty then the head is a null
reference.
4. Creating a Node
struct node{
int data; // A simple node of a linked list
node *next;
}*start;
start=NULL; /*start points at the first node
initialized to NULL at beginning*/
5. node* create( int num) //say num=1 is passed from main
{
node*ptr;
ptr= new node; //memory allocated dynamically
if(ptr==NULL)
printf(“OVERFLOW”); // no memory available
exit(1);
else
{
ptr->data=num;
ptr->next=NULL;
return ptr;
}
}
7. TYPES OF LINKED LIST
There are three basic types of linked lists :-
1. Singly linked list.
2. Doubly linked list.
3. Circular linked list.
8. SINGLY LINKED LIST
Singly linked lists contain nodes which have a data field as well as link
field.
Each node has only one link part.
Each link part contains the address of the next node in the list.
Link part of the last node contains NULL value which signifies the end
of the node.
9. Basic Operations on a list
Creating a List
Inserting an element in a list
Deleting an element from a list
Searching a list
Reversing a list
10. Inserting the node in a SLL
There are 3 cases here:-
Insertion at the beginning
Insertion at the end
Insertion after a particular node
11. Deleting a node from a SLL
There are 3 cases here:-
Deleting the first node
Deleting the last node
Deleting the intermediate node
12. Searching a SLL
Searching involves finding the required element in
the list.
We can use various techniques of searching like
linear search or binary search where binary
search is more efficient in case of Arrays
But in case of linked list since random access is
not available it would become complex to do binary
search in it.
We can perform simple linear search traversal .
13. Reversing a linked list
We can reverse a linked list by reversing the direction of the links between
2 nodes.
We make use of 3 structure pointers say p,q,r.
At any instant q will point to the node next to p and r will point to the
node next to q.
For next iteration p=q and q=r.
At the end we will change head to the last node
14. DOUBLY LINKED LIST
Doubly linked list is a linked data structure that consists of a set of
sequentially linked records called nodes.
Each node contains three fields :
:- one is data part which contain data only.
:- Two other field is links part that are point or references to the
previous or to the next node in the sequence of nodes.
The beginning and ending nodes' previous and next links, respectively,
point to some kind of terminator, typically a null node to facilitate
traversal of the list.
15. Can be traversed in either direction.
Some operations, such as deletion and inserting before a node, become easier.
16. Structure of DLL
struct node
{
int data;
node*next;
node*previous; //holds the address of previous node
};
17. INSERTING NODE IN DLL.
Inserting at beginning
Inserting at the end
Inserting after a node
19. CIRCULAR LINKED LIST
Circular Linked List is a variation of Linked list in which the first
element points to the last element and the last element points to the
first element.
Both Singly Linked List and Doubly Linked List can be made into a
circular linked list. For singly circular linked list:
20. In a circular linked list there are two methods
to know if a node is the first node or not.
Either a external pointer, list, points the first
node or
A header node is placed as the first node of the
circular list.
The header node can be separated from the
others by having a dedicated flag variable to
specify if the node is a header node or not.
