Data Structures Double Linked List C Program

Data Structures Lab Manual / Data Structures Double Linked List C Program

Program Name: Write a C Program for Double Linked List in Data Structures

Theory

Doubly linked list consists of a set of sequentially linked records called nodes. 
Each node contains three fields: two link fields (previous and next node) and one
data field. In Doubly linked list traversing can be done in both directions and 
displays the contents in the wholelist.

Program Code

#include<stdio.h>  
#include<stdlib.h>  

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

struct node *head;  
void insertion_beginning();  
void insertion_last();  
void insertion_specified();  
void deletion_beginning();  
void deletion_last();  
void deletion_specified();  
void display();  
void search(); 
 
void main ()  
{  
int choice =0;  

while(choice != 9)  
{  
printf("\nChoose \n1.Insert in begining\n
2.Insert at last\n
3.Insert at any random location\n
4.Delete from Beginning\n
5.Delete from last\n
6.Delete the node after the given data\n
7.Search Element\n
8. Display Elements\n9.Exit\n");  
scanf("\n%d",&choice);  

switch(choice)  
{  
case 1:insertion_beginning(); break;   
case 2:insertion_last();  break;   
case 3:insertion_specified(); break;   
case 4:deletion_beginning(); break;   
case 5:deletion_last();  break;  
case 6: deletion_specified(); break;  
case 7: search(); break;   
case 8: display(); break;  
case 9: exit(0); break;  
default:printf("Enter valid choice");  
}  
}  
}  

void insertion_beginning()  
{  
struct node *pointer;   
int item;  
pointer = (struct node *)malloc(sizeof(struct node));  

if(pointer == NULL)  
printf("\nOVERFLOW");  
else  
{  
printf("\nEnter Item value");  
scanf("%d",&item);  
     
if(head==NULL)  
{  
pointer->next = NULL;  
pointer->prev=NULL;  
pointer->data=item;  
head=pointer;  
}  
else   
{  
pointer->data=item;  
pointer->prev=NULL;  
pointer->next = head;  
head->prev=pointer;  
head=pointer;  
}  
printf("\nNode inserted\n");  
}  
     
}  



void insertion_last()  
{  
struct node *pointer,*temp;  
int item;  
pointer = (struct node *) malloc(sizeof(struct node));  
if(pointer == NULL)  
printf("\nOVERFLOW");  
 
else  
{  
printf("\nEnter value");  
scanf("%d",&item);  
pointer->data=item; 
 
if(head == NULL)  
{  
pointer->next = NULL;  
pointer->prev = NULL;  
head = pointer;  
}  

else  
{  
temp = head;  
while(temp->next!=NULL)  
temp = temp->next;  
 
temp->next = pointer;  
pointer ->prev=temp;  
pointer->next = NULL;  
}  
             
}  
printf("\nnode inserted\n");  
}  


void insertion_specified()  
{  
struct node *pointer,*temp;  
int item,loc,i;  
pointer = (struct node *)malloc(sizeof(struct node));  

if(pointer == NULL)  
printf("\n OVERFLOW");  
 
else  
{  
temp=head;  
printf("Enter the location");  
scanf("%d",&loc);  

for(i=0;i<loc;i++)  
{  
temp = temp->next;  
if(temp == NULL)  
{  
printf("\n There are less than %d elements", loc);  
return;  
}  
}  

printf("Enter value");  
scanf("%d",&item);  
pointer->data = item;  
pointer->next = temp->next;  
pointer -> prev = temp;  
temp->next = pointer;  
temp->next->prev=pointer;  
printf("\nnode inserted\n");  
}  
}  


void deletion_beginning()  
{  
struct node *pointer;  
if(head == NULL)  
printf("\n UNDERFLOW");  
 
else if(head->next == NULL)  
{  
head = NULL;   
free(head);  
printf("\nnode deleted\n");  
}  

else  
{  
pointer = head;  
head = head -> next;  
head -> prev = NULL;  
free(pointer);  
printf("\nnode deleted\n");  
}    
}  

void deletion_last()  
{  
struct node *pointer;  
if(head == NULL)  
printf("\n UNDERFLOW");  
 
else if(head->next == NULL)  
{  
head = NULL;   
free(head);   
printf("\nnode deleted\n");  
}  

else   
{  
pointer = head;   
if(pointer->next != NULL)  
pointer = pointer -> next;   


pointer -> prev -> next = NULL;   
free(pointer);  
printf("\nnode deleted\n");  
}  
}  

void deletion_specified()  
{  
struct node *pointer, *temp;  
int val;  
printf("\n Enter the data after which the node is to be deleted : ");  
scanf("%d", &val);  
pointer = head;  

while(pointer -> data != val)  
pointer = pointer -> next;  

if(pointer -> next == NULL)  
printf("\nCan't delete\n");  

else if(pointer -> next -> next == NULL)  
pointer ->next = NULL;  

else  
{   
temp = pointer -> next;  
pointer -> next = temp -> next;  
temp -> next -> prev = pointer;  
free(temp);  
printf("\nnode deleted\n");  
}     

}  


void display()  
{  
struct node *pointer;  
printf("\n Printing Double Linked List Node values\n");  
pointer = head;  
while(pointer != NULL)  
{  
printf("%d\n",pointer->data);  
pointer=pointer->next;  
}  
}  

 
void search()  
{  
struct node *pointer;  
int item,i=0,flag;  
pointer = head;   

if(pointer == NULL)  
printf("\nEmpty List\n");  

else  
{   
printf("\nEnter item which you want to search?\n");   
scanf("%d",&item);  

while (pointer!=NULL)  
{  

if(pointer->data == item)  
{  
printf("\nItem Found at Location %d ",i+1);  
flag=0;  
break;  
}   
else  
flag=1;  
i++;  
pointer = pointer -> next;  
}  


if(flag==1)  
printf("\nItem not found\n");  
}             
}

Input and Output:

Choose 
1.Insert in begining
2.Insert at last
3.Insert at any random location
4.Delete from Beginning
5.Delete from last
6.Delete the node after the given data
7.Search Element
8. Display Elements
9.Exit
1

Enter Item value10

Node inserted

Choose 
1.Insert in begining
2.Insert at last
3.Insert at any random location
4.Delete from Beginning
5.Delete from last
6.Delete the node after the given data
7.Search Element
8. Display Elements
9.Exit
1

Enter Item value20

Node inserted

Choose 
1.Insert in begining
2.Insert at last
3.Insert at any random location
4.Delete from Beginning
5.Delete from last
6.Delete the node after the given data
7.Search Element
8. Display Elements
9.Exit
7

Enter item which you want to search?
2

Item not found

Choose 
1.Insert in begining
2.Insert at last
3.Insert at any random location
4.Delete from Beginning
5.Delete from last
6.Delete the node after the given data
7.Search Element
8. Display Elements
9.Exit
20
Enter valid choice
Choose 
1.Insert in begining
2.Insert at last
3.Insert at any random location
4.Delete from Beginning
5.Delete from last
6.Delete the node after the given data
7.Search Element
8. Display Elements
9.Exit
8

 Printing Double Linked List Node values
20
10

Choose 
1.Insert in begining
2.Insert at last
3.Insert at any random location
4.Delete from Beginning
5.Delete from last
6.Delete the node after the given data
7.Search Element
8. Display Elements
9.Exit

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