/**
* C program to insert a node in Doubly linked list
*/
#include <stdio.h>
#include <stdlib.h>
/*
* Basic structure of Node
*/
struct node
{
int data;
struct node *prev;
struct node *next;
} *head, *last;
/*
* Function used in this program
*/
void createList(int n);
void displayList();
void insertAtBeginning(int data);
void insertAtEnd(int data);
void insertAtN(int data, int position);
int main()
{
int n, data, choice = 1;
head = NULL;
last = NULL;
/*
* Run forever until user chooses 0
*/
while (choice != 0)
{
/*
* Menu creation to use the program
*/
printf("============================================\n");
printf("DOUBLY LINKED LIST PROGRAM\n");
printf("============================================\n");
printf("1. Create List\n");
printf("2. Insert node - at beginning\n");
printf("3. Insert node - at end\n");
printf("4. Insert node - at N\n");
printf("5. Display list\n");
printf("0. Exit\n");
printf("--------------------------------------------\n");
printf("Enter your choice : ");
scanf("%d", &choice);
/*
* Choose from different menu operation
*/
switch (choice)
{
case 1:
printf("Enter the total number of nodes in list: ");
scanf("%d", &n);
createList(n);
break;
case 2:
printf("Enter data of first node : ");
scanf("%d", &data);
insertAtBeginning(data);
break;
case 3:
printf("Enter data of last node : ");
scanf("%d", &data);
insertAtEnd(data);
break;
case 4:
printf("Enter the position where you want to insert new node: ");
scanf("%d", &n);
printf("Enter data of %d node : ", n);
scanf("%d", &data);
insertAtN(data, n);
break;
case 5:
displayList();
break;
case 0:
break;
default:
printf("Error! Invalid choice. Please choose between 0-5");
}
printf("\n\n\n\n\n");
}
return 0;
}
/**
* Creates a doubly linked list of n nodes.
* @n Number of nodes to be created
*/
void createList(int n)
{
int i, data;
struct node *newNode;
if (n >= 1)
{
/*
* Create and link the head node
*/
head = (struct node *)malloc(sizeof(struct node));
printf("Enter data of 1 node: ");
scanf("%d", &data);
head->data = data;
head->prev = NULL;
head->next = NULL;
last = head;
/*
* Create and link rest of the n-1 nodes
*/
for (i = 2; i <= n; i++)
{
newNode = (struct node *)malloc(sizeof(struct node));
printf("Enter data of %d node: ", i);
scanf("%d", &data);
newNode->data = data;
newNode->prev = last; // Link new node with the previous node
newNode->next = NULL;
last->next = newNode; // Link previous node with the new node
last = newNode; // Make new node as last/previous node
}
printf("\nDOUBLY LINKED LIST CREATED SUCCESSFULLY\n");
}
}
/**
* Display content of the list from beginning to end
*/
void displayList()
{
struct node *temp;
int n = 1;
if (head == NULL)
{
printf("List is empty.\n");
}
else
{
temp = head;
printf("DATA IN THE LIST:\n");
while (temp != NULL)
{
printf("DATA of %d node = %d\n", n, temp->data);
n++;
/* Move the current pointer to next node */
temp = temp->next;
}
}
}
/**
* Inserts a new node at the beginning of the doubly linked list
* @data Data of the first node i.e. data of the new node
*/
void insertAtBeginning(int data)
{
struct node *newNode;
if (head == NULL)
{
printf("Error, List is Empty!\n");
}
else
{
newNode = (struct node *)malloc(sizeof(struct node));
newNode->data = data;
newNode->next = head; // Point to next node which is currently head
newNode->prev = NULL; // Previous node of first node is NULL
/* Link previous address field of head with newnode */
head->prev = newNode;
/* Make the new node as head node */
head = newNode;
printf("NODE INSERTED SUCCESSFULLY AT THE BEGINNING OF THE LIST\n");
}
}
/**
* Inserts a new node at the end of the doubly linked list
* @data Data of the last node i.e data of the new node
*/
void insertAtEnd(int data)
{
struct node *newNode;
if (last == NULL)
{
printf("Error, List is empty!\n");
}
else
{
newNode = (struct node *)malloc(sizeof(struct node));
newNode->data = data;
newNode->next = NULL;
newNode->prev = last;
last->next = newNode;
last = newNode;
printf("NODE INSERTED SUCCESSFULLY AT THE END OF LIST\n");
}
}
/**
* Inserts a node at any position in the doubly linked list
* @data Data of the new node to be inserted
* @position Position where to insert the new node
*/
void insertAtN(int data, int position)
{
int i;
struct node *newNode, *temp;
if (head == NULL)
{
printf("Error, List is empty!\n");
}
else
{
temp = head;
i = 1;
while (i < position - 1 && temp != NULL)
{
temp = temp->next;
i++;
}
if (position == 1)
{
insertAtBeginning(data);
}
else if (temp == last)
{
insertAtEnd(data);
}
else if (temp != NULL)
{
newNode = (struct node *)malloc(sizeof(struct node));
newNode->data = data;
newNode->next = temp->next; // Connect new node with n+1th node
newNode->prev = temp; // Connect new node with n-1th node
if (temp->next != NULL)
{
/* Connect n+1th node with new node */
temp->next->prev = newNode;
}
/* Connect n-1th node with new node */
temp->next = newNode;
printf("NODE INSERTED SUCCESSFULLY AT %d POSITION\n", position);
}
else
{
printf("Error, Invalid position\n");
}
}
}
Output
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 1
Enter the total number of nodes in list: 3
Enter data of 1 node: 10
Enter data of 2 node: 20
Enter data of 3 node: 30DOUBLY LINKED LIST CREATED SUCCESSFULLY
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 5
DATA IN THE LIST:
DATA of 1 node = 10
DATA of 2 node = 20
DATA of 3 node = 30
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 2
Enter data of first node : 1
NODE INSERTED SUCCESSFULLY AT THE BEGINNING OF THE LIST
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 5
DATA IN THE LIST:
DATA of 1 node = 1
DATA of 2 node = 10
DATA of 3 node = 20
DATA of 4 node = 30
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 3
Enter data of last node : 40
NODE INSERTED SUCCESSFULLY AT THE END OF LIST
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 5
DATA IN THE LIST:
DATA of 1 node = 1
DATA of 2 node = 10
DATA of 3 node = 20
DATA of 4 node = 30
DATA of 5 node = 40
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 4
Enter the position where you want to insert new node: 3
Enter data of 3 node : 15
NODE INSERTED SUCCESSFULLY AT 3 POSITION
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 5
DATA IN THE LIST:
DATA of 1 node = 1
DATA of 2 node = 10
DATA of 3 node = 15
DATA of 4 node = 20
DATA of 5 node = 30
DATA of 6 node = 40
============================================
DOUBLY LINKED LIST PROGRAM
============================================
1. Create List
2. Insert node - at beginning
3. Insert node - at end
4. Insert node - at N
5. Display list
0. Exit
--------------------------------------------
Enter your choice : 0
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