Question

Build a double linked list to accommodate the following numbers: 6,3,2,1,5, 0 in C Programming language

A. Print list forward

B. Sort the list

C. Delete a node with 3

D Print the list backwards

E. Insert a node with 10 between the first and the second nodes

Answer 1

#include<stdio.h>
#include<math.h>
#include<malloc.h>
//creatig node
struct node
{
   int data;
   struct node*next;
   struct node *prev;
};
void swapdata(struct node *temp,struct node *temp1)
{
   int d=temp->data;
   temp->data=temp1->data;
   temp1->data=d;
}
struct node *head;//head gloabl variable
struct node *insert(struct node *head,int x)//inserting node in the linked list(at end of list)
{
   struct node *newnode=(struct node*)malloc(sizeof(struct node));
   newnode->data=x;
   newnode->next=NULL;
   if(head==NULL)
   {
       newnode->prev=NULL;
       head=newnode;
   }
   else
   {
       struct node *temp=head;
       while(temp->next!=NULL)
       {
           temp=temp->next;
       }
       newnode->prev=temp;
       temp->next=newnode;
   }
   return head;
}
void printForward(struct node *head)//function to print data in forward direction
{
   struct node *t=head;
   while(t!=NULL)//travesign upto last value
   {
       printf("%d ",t->data);
       t=t->next;
   }
   printf("\n");
}
struct node *insertBetween(struct node *head,int value)//inserting node in between first and second nod
{
   struct node *temp=head;
   if(head==NULL)
   return head;
   if(head->next==NULL)
   return head;
   struct node *newnode=(struct node*)malloc(sizeof(struct node));
   newnode->data=value;
   newnode->prev=temp;
   newnode->next=temp->next;
   temp->next->prev=newnode;
   temp->next=newnode;
   return head;
}
struct node *Delete(struct node *head,int value)//deleting node having data 3
{
   if(head==NULL)
       return head;
   if(head->next==NULL)
   {
       free(head);
       head=NULL;
       return head;
   }
   struct node *temp=head;
   while(temp->data!=value)
   {
       temp=temp->next;
   }
  
   temp->prev->next=temp->next;
   temp->next->prev=temp->prev;
   free(temp);
  
   return head;
}
void sort(struct node *head) //sorting data in the linked list usign bubble sort
{
int f, i;
struct node *temp;
struct node *temp1 = NULL;

/* Checking for empty list */
if (head == NULL)
return;

do
{
f = 0;
temp = head;
while (temp->next != temp1)
{
if (temp->data > temp->next->data)
{
swapdata(temp, temp->next);
f = 1;
}
temp= temp->next;
}
temp1 = temp;
}
while (f);
}

void printBackward(struct node *head)//printing data in backward order
{
   struct node *t=head;
   while(t->next!=NULL)//traversing upto last node
       {
           t=t->next;
       }
   while(t!=NULL)//traversing in backward using prev pointer
   {
       printf("%d ",t->data);
       t=t->prev;  
   }  
   printf("\n");
}
int main()
{
   head=insert(head,6);
   head=insert(head,3);
   head=insert(head,2);
   head=insert(head,1);
   head=insert(head,5);
   head=insert(head,0);
   printf("Forward traversing\n");
   printForward(head);
   printf("Backward traversing\n");
   printBackward(head);
   printf("After inserting Node 10 in between first and second node\n");
   head=insertBetween(head,10);
   printForward(head);
   printf("After deleting node 3\n");
   head=Delete(head,3);
   printForward(head);
   printf("After Sorting\n");
   sort(head);
   printForward(head);
  
}