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DoublyLinkedList.c
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DoublyLinkedList.c
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// C program for the all operations in the Doubly Linked List
#include <stdio.h>
#include <stdlib.h>
// Structure of a Doubly Linked List
struct node {
int data;
struct node *prev;
struct node *next;
};
struct node* head = NULL;
// Traversal of a Doubly Linked List
void traversal()
{
// if head of linked list is NULL or the linked list is empty
if (head == NULL) {
printf("\nList is empty\n");
return;
}
// Otherwise print the data by traversing the linked list
struct node* temp;
temp = head;
while (temp != NULL) {
printf("Data = %d\n", temp->data);
temp = temp->next;
}
}
// Function to insert an element at the front of the Doubly Linked list
void insertAtFront()
{
int data;
struct node* temp;
temp = (struct node*)malloc(sizeof(struct node));
printf("\nEnter number to be inserted: ");
scanf("%d", &data);
temp->data = data;
temp->prev = NULL;
temp->next = head;
head = temp;
}
// Function to insert an element at the end of the Doubly Linked list
void insertAtEnd()
{
int data;
struct node *temp, *ptr;
temp = (struct node*)malloc(sizeof(struct node));
temp->prev = NULL;
temp->next = NULL;
printf("\nEnter number to be inserted: ");
scanf("%d", &data);
temp->data = data;
temp->next = NULL;
ptr = head;
if (head == NULL) {
head = temp;
}
else {
while (ptr->next != NULL)
ptr = ptr->next;
temp->prev = ptr;
ptr->next = temp;
}
}
// Function to insert an element at a given index of the Doubly Linked list
void insertAtPosition()
{
int data, pos, i = 1;
struct node *temp, *newnode;
newnode = malloc(sizeof(struct node));
newnode->next = NULL;
newnode->prev = NULL;
printf("\nEnter position : ");
scanf("%d", &pos);
if (head == NULL) {
head = newnode;
newnode->prev = NULL;
newnode->next = NULL;
}else if (pos == 1) {
insertAtFront();
}else {
printf("\nEnter number to be inserted: ");
scanf("%d", &data);
newnode->data = data;
temp = head;
while (i < pos - 1) {
temp = temp->next;
i++;
}
newnode->next = temp->next;
newnode->prev = temp;
temp->next = newnode;
temp->next->prev = newnode;
}
}
// Function to delete front element of the Doubly Linked list
void deleteFirst()
{
struct node* temp;
if (head == NULL)
printf("\nList is empty\n");
else {
temp = head;
head = temp->next;
if (head != NULL)
head->prev = NULL;
free(temp);
}
}
// Function to delete last element of the Doubly Linked list
void deleteEnd()
{
struct node* temp;
if (head == NULL)
printf("\nList is empty\n");
temp = head;
while (temp->next != NULL)
temp = temp->next;
if (head->next == NULL)
head = NULL;
else {
temp->prev->next = NULL;
free(temp);
}
}
// Function to delete an element of a given index of the Doubly Linked list
void deletePosition()
{
int pos, i = 1;
struct node *temp, *position;
temp = head;
if (head == NULL)
printf("\nList is empty\n");
else {
printf("\nEnter position : ");
scanf("%d", &pos);
if (pos == 1) {
deleteFirst();
if (head != NULL) {
head->prev = NULL;
}
free(position);
return;
}
while (i < pos - 1) {
temp = temp->next;
i++;
}
position = temp->next;
if (position->next != NULL)
position->next->prev = temp;
temp->next = position->next;
free(position);
}
}
int main()
{
int choice;
while (1) {
// Choose t1 to traverse and print the list
// Choose t2 to insert an element at the front
// Choose t3 to insert an element at the end
// Choose t4 to insert an element at a given position
// Choose t5 to delete the first element
// Choose t6 to delete the last element
// Choose t7 to delete an element of a given position
// Choose t8 to exit the program
printf("\n\t1 To see list\n");
printf("\t2 For insertion at"
" starting\n");
printf("\t3 For insertion at"
" end\n");
printf("\t4 For insertion at "
"any position\n");
printf("\t5 For deletion of "
"first element\n");
printf("\t6 For deletion of "
"last element\n");
printf("\t7 For deletion of "
"element at any position\n");
printf("\t8 To exit\n");
printf("\nEnter Choice :\n");
scanf("%d", &choice);
switch (choice) {
case 1:
traversal();
break;
case 2:
insertAtFront();
break;
case 3:
insertAtEnd();
break;
case 4:
insertAtPosition();
break;
case 5:
deleteFirst();
break;
case 6:
deleteEnd();
break;
case 7:
deletePosition();
break;
case 8:
exit(1);
break;
default:
printf("Wrong Choice \n");
continue;
}
}
return 0;
}