WRITE A MENU DRIVEN PROGRAM IN "C" FOR DOUBLY LINK LIST WITH ALL OPERATIONS USING SWITCH CASE.

Doubly Linked List | Set 1 (Introduction and Insertion)

We strongly recommend to refer following post as a prerequisite of this post.

A Doubly Linked List (DLL) contains an extra pointer, typically called previous pointer, together with next pointer and data which are there in singly linked list.

             PROGRAM ON DOUBLY LINKLIST

#include<stdio.h>
#include<conio.h>

typedef struct node
 {
  struct node *prev;
  int data;
  struct node *next;
}node;

node *root=NULL;

void insert()
{
  node *temp;
  temp=(node*)malloc(sizeof(node));
  printf("Enter node data (rollno)\n");
  scanf("%d",&temp->data);
  temp->prev=NULL;
  temp->next=NULL;
if(root==NULL)
  {
   root=temp;
  }
else
 {
  node *p;
  p=root;
while(p->next!=NULL)
   {
     p=p->next;
   }
    p->next=temp;
    temp->prev=p;
 }
}
void insertf()
{
node *temp;
temp=(node*)malloc(sizeof(node));
printf("Enter node data (rollno)\n");
scanf("%d",&temp->data);
temp->next=NULL;
temp->prev=NULL;
if(root==NULL)
 {
   root=temp;
 }
else
 {
  temp->next=root;
  root->prev=temp;
  root=temp;
 }
}

int length()
{
 node *temp;
 int a=0;
 temp=root;
 while(temp!=NULL)
 {
  a++;
  temp=temp->next;
 }
return a;
}

void display()
{
node *temp;
temp=root;
if(temp==NULL)
 {
  printf("List is empty\n");
 }
else
 {
  while(temp!=NULL)
    {
      printf("%3d",temp->data);
      temp=temp->next;
    }
 }
}

void insertp()
{
 int pos,len,i=1;
 node *temp,*p;
 printf("Enter location to add\n");
 scanf("%d",&pos);
 len=length();
  if(pos>len)
   {
     printf("Invalid location\n");
     printf("List contain %d data\n",len);
   }
   else
   {
     temp=(node*)malloc(sizeof(node));
     printf("Enter node data(rollno)\n");
     scanf("%d",&temp->data);
     temp->next=NULL;
     temp->prev=NULL;
     p=root;
   while(i<pos)
      {
 p=p->next;
 i++;
      }
 temp->next=p->next;
 p->next->prev=temp;
 temp->prev=p;
 p->next=temp;
}
}

void deleted()
{
node *temp,*p,*q;
int pos,len,i=1;
printf("\nEnter the node position to delete\n");
scanf("%d",&pos);
len=length();
 if(pos>len)
  {
    printf("Invalid location\n");
    printf("List contain %d data\n",len);
  }
else if(pos==1)
   {
     temp=root;
     root=root->next;
     root->prev=NULL;
     free(temp);
   }
else if(pos>1&&pos!=len)
    {
      p=root;
while(i<pos-1)
   {
    p=p->next;
    i++;
   }
 q=p->next;
 p->next=q->next;
 q->next->prev=p;
 q->prev=NULL;
 q->next=NULL;
 free(q);
}
else if(pos==len&&length()>1)
 {
   i=1;
   len=length();
   printf("Length %d\n", len);
   p=root;
while(i!=len)
  {
    p=p->next;
    i++;
  }
 p->prev->next=NULL;
 free(p);
}
}

void modify()
{
   int a,b=0;
   node *p;
   p=root;
   printf("\nEnter the data to be modified \n");
   scanf("%d",&a);
while(p!=NULL)
 {
  if(p->data==a)
   {
     printf("\nEnter the data  ");
     scanf("%d",&p->data);
     b=1;
     break;
   }
   p=p->next;
 }
if(b==0)
 printf("Data not found");
}

void displayrev()
{
  int a[20]={0},i=1,j;
  node *temp;
  temp=root;
if(temp==NULL)
  {
   printf("List is empty\n");
  }
else
  {
while(temp!=NULL)
  {
   a[i]=temp->data;
   temp=temp->next;
   i++;
  }
i--;
for(j=i;j>0;j--)
  {
    printf("%3d",a[j]);
  }
  }
}

int menu()
{
int a;
printf("\n*****menu*****");
printf("\nEnter 1 to Insert a record.");
printf("\nEnter 2 Insert a record at first");
printf("\nEnter 3 Insert a record at particular position");
printf("\nEnter 4 to Delete a record.");
printf("\nEnter 5 to Modify a record.");
printf("\nEnter 6 to Display a record.");
printf("\nEnter 7 to dispaly a record in reverse.");
printf("\nEnter 8 to Exit.");
printf("\nEnter your choice : ");
scanf("%d",&a);
return a;
}
int main()
{
int r;
clrscr();
do
{
switch(r=menu())
{
 case 1:insert();
 break;
 case 2:insertf();
 break;
 case 3:insertp();
 break;
 case 4:deleted();
 break;
 case 5:modify();
 break;
 case 6:display();
 break;
 case 7:displayrev();
 break;
 case 8:printf("\n****Thankyou****");
 break;
}
}while(r!=8);
getch();
return 0;
}