DOUBLY LINKED LIST OPERATIONS

#include<stdio.h>

#include<conio.h>

#include<alloc.h>

#include<stdlib.h>

# define NULL0

typedef struct list

{

int data;

struct list *next;

struct list *prev;

}node;

node *head = NULL;

node *prev = NULL;

node* create_node()

{

node *new1;

new1 =(node *) malloc(sizeof(node));

printf("\nEnter data:");

scanf("%d",&new1->data);

new1->next = NULL;

new1->prev = NULL;

return(new1);

}

void insert_beg()

{

node *new1;

if(head == NULL)

{

printf("\nlist is empty:");

new1 = create_node();

head = new1;

}

else

{

new1 = create_node();

new1->next = head;

new1->prev = NULL;

head = new1;

}

}

void insert_after()

{

int insdata;

node *new1,*temp;

printf("\nEnter data after which to insert:");

scanf("%d",&insdata);

temp = head;

while(temp != NULL)

{

if(temp->data == insdata)

{

new1 = create_node();

new1->next = temp->next;

temp->next = new1;

return;

}

else

temp = temp->next;

}

}

void search()

{

int insdata,b=1;

node *temp;

printf("\nEnter data to be searched:");

scanf("%d",&insdata);

temp = head;

while(temp != NULL)

{

if(temp->data == insdata)

{

printf("\nData found in %d node",b);

return;

}

else

{

temp = temp->next;

b++;

}

}

printf("Data not found");

}

void display()

{

node *temp;

temp = head;

while(temp != NULL)

{

printf("\n%d",temp->data);

temp = temp->next;

}

}

node * find_prev(int x)

{

node *temp,*prev;

temp = head->next;

prev = head;

while(temp->next != NULL && temp->data != x)

{

prev = temp;

temp = temp->next;

}

printf("\nprevious data = %d",*prev);

return(prev);

}

void deletion()

{

node *temp,*temp1;

int x;

printf("\nEnter the data to be deleted:");

scanf("%d",&x);

temp = head;

temp1=head->next;

if(temp->data == x)

{

head = temp->next;

free(temp);

}

else

{

while(temp1!=NULL)

{

if(temp1->data == x)

{

temp->next = temp1->next;

free(temp1);

return;

}

else

{

temp1=temp1->next;

temp=temp->next;

}}}}

void main()

{

int ch,ch1,x;

clrscr();

do

{

printf("\nMENU");

printf("\n1.create a node\n2.insert a node\n3.search\n4.Display\n5.Find previous\n6.Delete\n7.exit");

printf("\nEnter choice");

scanf("%d",&ch);

switch(ch)

{

case 1: head = create_node();

break;

case 2: printf("1.Insert at begining\n2.insert after");

printf("Enter choice");

scanf("%d",&ch1);

if(ch1 == 1)

insert_beg();

else

insert_after();

break;

case 3: search();

break;

case 4: display();

break;

case 5: printf("\nEnter the data to be found");

scanf("%d",&x);

find_prev(x);

break;

case 6: deletion();

break;

case 7: exit(0);

}

printf("\n\n");

}while(ch != 7);

getch();

}

Output:

MENU

1.create a node

2.insert a node

3.search

4.Display

5.Find previous

6.Delete

7.exit

Enter choice1

Enter data:2

MENU

1.create a node

2.insert a node

3.search

4.Display

5.Find previous

6.Delete

7.exit

Enter choice2

1.Insert at begining

2.insert afterEnter choice1

Enter data:4

MENU

1.create a node

2.insert a node

3.search

4.Display

5.Find previous

6.Delete

7.exit

Enter choice2

1.Insert at begining

2.insert afterEnter choice2

Enter data after which to insert:5

MENU

1.create a node

2.insert a node

3.search

4.Display

5.Find previous

6.Delete

7.exit

Enter choice4

4

2

MENU

1.create a node

2.insert a node

3.search

4.Display

5.Find previous

6.Delete

7.exit

Enter choice3

Enter data to be searched:2

Data found in 2 node

MENU

1.create a node

2.insert a node

3.search

4.Display

5.Find previous

6.Delete

7.exit

Enter choice6

Enter the data to be deleted:4

MENU

1.create a node

2.insert a node

3.search

4.Display

5.Find previous

6.Delete

7.exit

Enter choice4

2