This document describes a menu-driven C program that implements a doubly linked list. The program allows the user to perform operations like creation, insertion, deletion, sorting, and searching of nodes in the doubly linked list. The main functions include create() to create nodes, display() to print the list, insert() to add nodes at different positions, delete() to remove nodes, sort() to sort the list, and find() to search for a node. The program uses a menu to allow the user to select the desired operation on the doubly linked list.

1. DOUBLE LINKED LIST
A Menu Driven Program In C

2. The Basic Declarations
#include<stdio.h>
#include<stdlib.h>
void mainmenu(), create(), display(), insert(), insert_first(),insert_between(),insert_end(), deletion(),
delete_first(),delete_position(),delete_end(),
sort(),reverse(),find();
int count();
struct node
{
struct node *prev;
int info;
struct node *next;
};
typedef struct node NODE;
NODE *start=NULL;
int main()
{
mainmenu();
}

3. The Mainmenu Function
void mainmenu()
{
int choice,x;
while(1)
{
printf("n----MAIN MENU----n");
printf("1. Create.n");
printf("2. Display.n");
printf("3. Insert.n");
printf("4. Count.n");
printf("5. Delete.n");
printf("6. Sorting.n");
printf("7. Reverse.n");
printf("8. Find.n");
printf("9. Exit.n");
printf("Enter choice: ");
scanf("%d",&choice);
switch(choice)
{
case 1: create();
break;
case 2: display();
break;
case 3: insert();
break;
case 4: x=count();
printf("The number of elements are %d",x);
break;
case 5: deletion();
break;
case 6: sort();
break;
case 7: reverse();
break;
case 8: find();
break;
case 9: exit(0);
break;
default: printf("Enter a valid choice.");
}
}
}

4. Creation Of Nodes
void create()
{
NODE *temp, *traverse;
int iData;
temp=(NODE*)malloc(sizeof(NODE));
temp->prev=NULL;
temp->next=NULL;
printf("Enter an integer value: ");
scanf("%d",&iData);
temp->info=iData;
if(start==NULL)
{
start=temp;
}
else
{
traverse=start;
while(traverse->next!=NULL)
{
traverse=traverse->next;
}
traverse->next=temp;
temp->prev=traverse;
}
}

5. Display Of The Nodes
void display()
{
NODE *traverse;
if(start==NULL)
{
printf("There are no nodes to be displayed. The list is
empty.n");
}
else
{
traverse=start;
printf("The linked list is: ");
while(traverse!=NULL)
{
printf("%d ",traverse->info);
traverse=traverse->next;
}
}
}

6. The Insert Menu
void insert()
{
int choice;
while(1)
{
printf("n---Insert Menu---n");
printf("1. Insert at first position.n");
printf("2. Insert in between.n");
printf("3. Insert at the end.n");
printf("4. Go to main menun");
printf("5. Exitn");
printf("Enter choice: ");
scanf("%d",&choice);
switch(choice)
{
case 1: insert_first();
break;
case 2: insert_between();
break;
case 3: insert_end();
break;
case 4: mainmenu();
break;
case 5: exit(0);
break;
default: printf("Enter a valid choice.");
}
}
}

7. Insert Node At The First Position
void insert_first()
{
NODE *temp;
if(start==NULL)
{
printf("List is empty. Create as the first node.n");
create();
}
else
{
int iData;
temp=(NODE *)malloc(sizeof(NODE));
temp->prev=NULL;
temp->next=NULL;
printf("Enter an integer value: ");
scanf("%d",&iData);
temp->info=iData;
start->prev=temp;
temp->next=start;
start=temp;
printf("Node inserted at first position.n");
}
display();
}

8. Insert Node At Any Position
void insert_between()
{
if(start==NULL)
{
printf("List is empty. Create as the first node.n");
create();
}
else
{
int iPosition,iCount,iLoop,iData;
printf("Enter the position where you want to insert: ");
scanf("%d",&iPosition);
iCount=count();
if(iPosition>iCount)
{
printf("There are %d elements.n",iCount);
}
else
{
NODE *temp,*traverse;
traverse=start;
printf("Enter an integer value: ");
scanf("%d",&iData);
temp = (NODE *)malloc(sizeof(NODE));
temp->prev=NULL;
temp->info=iData;
temp->next=NULL;
for(iLoop=0;iLoop<iPosition-2;iLoop++)
{
traverse=traverse->next;
}
temp->prev=traverse;
temp->next=traverse->next;
traverse->next->prev=temp;
traverse->next=temp;
printf("Node inserted at position %d.n",iPosition);
}
}
display();
}

9. Insert Node At The End
void insert_end()
{
if(start==NULL)
{
printf("List is empty. Create as the first node.n");
create();
}
else
{
create();
printf("Node inserted at the end.n");
}
display();
}

10. Counting Of Nodes
int count()
{
int iCount=0;
NODE *traverse;
traverse=start;
while(traverse!=NULL)
{
traverse=traverse->next;
iCount++;
}
return iCount;
}

11. The Delete Menu
void deletion()
{
int choice;
while(1)
{
printf("n---Delete Menu---n");
printf("1. Delete first node.n");
printf("2. Delete last node.n");
printf("3. Delete by position.n");
printf("4. Go to main menun");
printf("5. Exitn");
printf("Enter choice: ");
scanf("%d",&choice);
switch(choice)
{
case 1: delete_first();
break;
case 2: delete_end();
break;
case 3: delete_position();
break;
case 4: mainmenu();
break;
case 5: exit(0);
break;
default: printf("Enter a valid choice.");
}
}
}

12. Delete The First Node
void delete_first()
{
NODE *delete_node;
if(start==NULL)
{
printf("There are no nodes to be deleted. The list is
empty.n");
}
else
{
delete_node=start;
start=start->next;
free(delete_node);
printf("The first node is deleted.n");
}
display();
}

13. Delete The Last Node
void delete_end()
{
NODE *delete_node, *traverse;
if(start==NULL)
{
printf("There are no nodes to be deleted. The list is
empty.n");
}
else
{
traverse=start;
while(traverse->next->next!=NULL)
{
traverse=traverse->next;
}
delete_node=traverse->next;
traverse->next=NULL;
free(delete_node);
printf("The last node is deleted.n");
}
display();
}

14. Delete Node At Any Position
void delete_position()
{
if(start==NULL)
{
printf("There are no nodes to be deleted. The list is empty.n");
}
else
{
NODE *traverse, *delete_node;
int iPosition, iLoop, iCount;
printf("Enter the position to be deleted: ");
scanf("%d",&iPosition);
iCount=count();
if(iPosition>iCount)
{
printf("There are %d elements.n",iCount);
}
else
{
traverse=start;
for(iLoop=0;iLoop<iPosition-2;iLoop++)
{
traverse=traverse->next;
}
delete_node=traverse->next;
delete_node->next->prev=traverse;
traverse->next=delete_node->next;
free(delete_node);
printf("Node deleted at position %d.n",iPosition);
}
}
display();
}

15. Sorting
void sort()
{
static NODE *traverse1;
traverse1=start;
NODE *traverse2;
int iOuter_Loop,iInner_Loop,iCount,iTemp;
iCount=count();
for(iOuter_Loop=0;iOuter_Loop<iCount-1;iOuter_Loop++)
{
traverse2=traverse1->next;
for(iInner_Loop=iOuter_Loop+1;iInner_Loop<iCount;iInner_Loop++)
{
if(traverse1->info>traverse2->info)
{
iTemp=traverse1->info;
traverse1->info=traverse2->info;
traverse2->info=iTemp;
}
traverse2=traverse2->next;
}
traverse1=traverse1->next;
}
printf("Nodes sortedn");
display();
}

16. Reversal Of The List
void reverse()
{
NODE *previous, *current;
previous=start;
current=previous->next;
previous->prev=current;
previous->next=NULL;
while(current!=NULL)
{
current->prev=current->next;
current->next=previous;
previous=current;
current=current->prev;
}
start=previous;
printf("Nodes reversedn");
display();
}

17. Searching
void find()
{
int iData;
NODE *traverse;
printf("Enter a number to be searched: ");
scanf("%d",&iData);
traverse=start;
while(traverse!=NULL)
{
if(traverse->info==iData)
{
printf("Element found.");
return;
}
else
{
traverse=traverse->next;
}
}
printf("Element not found.");
}

18. Presented By:
Sayantan Sur
Thank You