Doubly linked list Implementation code is given below:
//code for Implementation of Doubly linked list
#include<stdio.h>
#include<stdlib.h>
struct node{
int data;
struct node *ll,*rl;
}*head=NULL;
struct node *tail;
int count()
{
int length = 0;
struct node *t;
t=head;
while(t != NULL)
{
length++;
t = t ->rl;
}
return length;
}
void insertbeg(int item)
{
struct node* newnode;
newnode = (struct node*)malloc(sizeof(struct node));
newnode->data = item;
newnode->ll=newnode->rl=NULL;
if(head == NULL)
{
head = tail = newnode;
}
else{
newnode->rl=head;
head->ll = newnode;
head = newnode;
}
}
void insertend(int item)
{
struct node* newnode;
newnode = (struct node*)malloc(sizeof(struct node));
newnode->data = item;
newnode->ll=newnode->rl=NULL;
if(head == NULL)
{
head = tail = newnode;
}
else{
tail->rl=newnode;
newnode->ll=tail;
tail=newnode;
}
}
void insertpos(int item,int pos)
{
struct node* newnode,*t;
newnode = (struct node*)malloc(sizeof(struct node));
newnode->data = item;
newnode->ll=newnode->rl=NULL;
if(pos > count())
{
printf("\nInvalid position");
}
else if(pos == 1)
{
insertbeg(item);
}
else{
t = head;
for(int i =1;i<pos-1;i++)
{
t=t->rl;
}
newnode->ll= t;
newnode->rl=t->rl;
t->rl=newnode;
t->rl->ll=newnode;
}
}
void deletebeg()
{
struct node *t;
if(head == NULL)
{
printf("\n List is empty");
}
else if(head->rl==NULL)
{
printf("\n Deleted data is %d",head->data);
tail = head = NULL;
}
else{
t=head;
head = head->rl;
head->ll=NULL;
printf("\n Deleted data is %d",t->data);
free(t);
}
}
void deleteend()
{
struct node*t;
if(head == NULL)
{
printf("\n List is empty");
}
else if(head->rl==NULL)
{
printf("\n Deleted data is %d",head->data);
tail = head = NULL;
}
else{
t=tail;
tail= tail->ll;
tail->rl=NULL;
printf("\n Deleted data is %d",t->data);
free(t);
}
}
void deletepos(int pos)
{
if(pos > count())
{
printf("\nInvalid position");
}
else if(pos == 1)
{
deletebeg();
}
else if(pos == count())
{
deleteend();
}
else{
struct node *t,*p;
t=head;
for(int i=1;i<pos-1;i++)
{
t=t->rl;
}
p=t->rl;
t->rl=p->rl;
p->rl->ll=t;
printf("\n Deleted data is %d",p->data);
free(p);
}
}
void display()
{
struct node* temp;
temp=head;
if(head == NULL)
{
printf("List is Empty");
}
else{
while(temp != NULL)
{
printf("_%d_",temp->data);
temp = temp ->rl;
}
}
}
void main()
{
int choice ,c,data,x;
do{
printf("press 1 to insert in begning\n");
printf("press 2 to insert in end\n");
printf("press 3 to insert in any positions\n");
printf("press 4 to delete first element\n");
printf("press 5 to delete end element\n");
printf("press 6 to to delete in any position\n");
printf("press 7 to display\n");
printf("press 8 for the length of current list\n");
printf("press 0 to Exit\n");
fflush(stdin);
scanf(" %d",&choice);
switch(choice)
{
case 1 :
printf(" Enter the data to insert :");
scanf(" %d",&data);
insertbeg(data);
break;
case 2 :
printf(" Enter the data to insert :");
scanf(" %d",&data);
insertend(data);
break;
case 3 :
printf(" Enter the data to insert :");
scanf(" %d",&data);
printf(" Enter the position to insert :");
scanf(" %d",&x);
insertpos(data,x);
break;
case 4 :
deletebeg();
break;
case 5 :
deleteend();
break;
case 6 :
printf(" Enter the position to delete :");
scanf(" %d",&x);
deletepos(x);
break;
case 7 :
display();
break;
case 8 :
printf("\n the length of current list: %d",count());
break;
case 0:
exit(1);
break;
default:
printf("\nEnter the correct value");
}
printf("\nEnter 1 to continue :");
fflush(stdin);
scanf(" %d",&c);
}while(c==1);
}Output
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
1
Enter the data to insert :55
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
7
_55__22__11__33__66_
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
5
deleted element is 66
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
7
_55__22__11__33_
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
6
Enter the position to delete :2
deleted element is 22
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
7
_55__11__33_
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
8
the length of current list :3
Enter 1 to continue :1
press 1 to insert in begning
press 2 to insert in end
press 3 to insert in any positions
press 4 to delete first element
press 5 to delete end element
press 6 to to delete in any position
press 7 to display
press 8 for the length of current list
press 0 to Exit
0
