Insertion at specific position in Circular Linked List in C++
February 16, 2023
How we can insert data at specific position in circular linked list?
Insertion at specific position in circular linked list in C++ is one the insertion operation that we can perform on the circular linked list. In this article we will be learning steps and algorithm to do the same. We can perform insertion at following places also:-
Insertion at the beginning of the circular linked list.
Insertion at the end of the circular linked list.
Steps to insert new node at specific position in circular linked list in CPP
If the circular linked list is empty, terminate function.
Else define two node pointers.
Create new node and stor the data in the new node
Now traverse till the specific position and insert this new node there.
Link the pointer of this new node to the node present at this place previously.
Print the new circular linked list to see the result.
Syntax
class Node { int data; Node *next; };
Algorithm to write a CPP program to insert at specific position in Circular Linked List
#include<iostream>
using namespace std;
struct Node
{
int num;
struct Node *next;
} *head;
void insertStart (struct Node **head, int data) //function to create linked list
{
struct Node *newNode = (struct Node *) malloc (sizeof (struct Node));
newNode->num = data;
// if its the first node being entered
if (*head == NULL)
{
*head = newNode; // assigning itself as head
(*head)->next = *head; // assigning itself as next node
cout << newNode->num << " Inserted\n";
return;
}
// if CLL already as >=1 node
struct Node *curr = *head;
// traverse till last node in CLL
while (curr->next != *head)
{
curr = curr->next;
}
curr->next = newNode; // last node's next as this new node
newNode->next = *head; // new node's next as current head node
*head = newNode; // changing head node to this new node
cout << newNode->num << " Inserted\n";
// previous head node becomes 2nd node
}
void insertSpecific(struct Node **head,int num, int pos)//function to insert element at specific position
{
struct Node *newnode, *curNode;
int i;
if(*head == NULL)
{
cout<<"List is empty";
}
else
{
newnode = (struct Node *)malloc(sizeof(struct Node));
newnode->num = num;
curNode = *head;
for(i=0; i<=pos-3; i++) { curNode = curNode->next;
}
newnode->next = curNode->next;
curNode->next = newnode;
}
}
void display (struct Node *head)
{
cout << "\nCircular Linked List : " << endl;
// if circular linked list is empty currently
if (head == NULL)
return;
struct Node *temp = head;
// since we need to take care of circular nature of linked list
do
{
cout << temp->num << " ";
temp = temp->next;
}
while (temp != head);
cout << endl;
}
int main () //main function
{
// first node will be null at creation
struct Node *head = NULL;
insertStart (&head, 1);
insertStart (&head, 2);
insertStart (&head, 3);
insertStart (&head, 4);
insertStart (&head, 5);
cout<<"Before insertion ";
display (head);
insertSpecific (&head,8,2);
cout<<"After insertion ";
display (head);
return 0;
}
Output:
1 Inserted
2 Inserted
3 Inserted
4 Inserted
5 Inserted
Before insertion
Circular Linked List :
5 4 3 2 1
After insertion
Circular Linked List :
5 8 4 3 2 1
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