Develop a ‘C’ program to create and implement a SINGLY LINKED LIST. Write functions to insert, delete, and display elements of the list.

 

DATA STRUCTURE & ALGORITHM USING C – LAB (2018407)

UNIT – 01:

Develop a ‘C’ program to create and implement a SINGLY LINKED LIST. Write functions to insert, delete, and display elements of the list.

Program:

#include <stdio.h>
#include <stdlib.h>
/* Structure of a node */
struct node {
int data; // Data
struct node *next; // Address
}*head;
void createList(int n);
void insertNodeAtBeginning(int data);
void displayList();
int main()
{
int n, data;
/*
* Create a singly linked list of n nodes
*/
printf("Enter the total number of nodes: ");
scanf("%d", &n);
createList(n);
printf("\nData in the list \n");
displayList();
/*
* Insert data at the beginning of the singly linked list
*/
printf("\nEnter data to insert at beginning of the list: ");
scanf("%d", &data);
insertNodeAtBeginning(data);
printf("\nData in the list \n");
displayList();
return 0;
}
/*
* Create a list of n nodes
*/
void createList(int n)
{
struct node *newNode, *temp;
int data, i;
head = (struct node *) malloc (sizeof(struct node));
/*
* If unable to allocate memory for head node
*/
if(head == NULL)
{
printf("Unable to allocate memory.");
}
else
{
printf("Enter the data of node 1: ");
scanf("%d", &data);
head->data = data; // Link data field with data
head->next = NULL; // Link address field to NULL
temp = head;
for(i=2; i<=n; i++)
{
newNode = (struct node *)malloc(sizeof(struct node));
/* If memory is not allocated for newNode */
if(newNode == NULL)
{
printf("Unable to allocate memory.");
break;
}
else
{
printf("Enter the data of node %d: ", i);
scanf("%d", &data);
newNode->data = data; // Link data field of newNode with data
newNode->next = NULL; // Link address field of newNode with NULL
temp->next = newNode; // Link previous node i.e. temp to the newNode
temp = temp->next;
}
}
printf("SINGLY LINKED LIST CREATED SUCCESSFULLY\n");
}
}
/*
* Create a new node and inserts at the beginning of the linked list.
*/
void insertNodeAtBeginning(int data)
{
struct node *newNode;
newNode = (struct node*)malloc(sizeof(struct node));
if(newNode == NULL)
{
printf("Unable to allocate memory.");
}
else
{
newNode->data = data; // Link data part
newNode->next = head; // Link address part
head = newNode; // Make newNode as first node
printf("DATA INSERTED SUCCESSFULLY\n");
}
}
/*
* Display entire list
*/
void displayList()
{
struct node *temp;
/*
* If the list is empty i.e. head = NULL
*/
if(head == NULL)
{
printf("List is empty.");
}
else
{
temp = head;
while(temp != NULL)
{
printf("Data = %d\n", temp->data); // Print data of current node
temp = temp->next; // Move to next node
}
}
}
Output:
 
Enter the total number of nodes: 4
Enter the data of node 1: 20
Enter the data of node 2: 30
Enter the data of node 3: 40
Enter the data of node 4: 50
 
SINGLY LINKED LIST CREATED SUCCESSFULLY
Data in the list
Data = 20
Data = 30
Data = 40
Data = 50
Enter data to insert at beginning of the list: 10

 

DATA INSERTED SUCCESSFULLY
Data in the list
Data = 10
Data = 20
Data = 30
Data = 40
Data = 50