Insertion in singly linked list at beginning

Inserting a new element into a singly linked list at beginning is quite simple. We just need to make a few adjustments in the node links. There are the following steps which need to be followed in order to inser a new node in the list at beginning.

Allocate the space for the new node and store data into the data part of the node. This will be done by the following statements.

ptr = (struct node *) malloc(sizeof(struct node *));
			ptr → data = item 

Make the link part of the new node pointing to the existing first node of the list. This will be done by using the following statement.

At the last, we need to make the new node as the first node of the list this will be done by using the following statement.

Algorithm

Step 1: IF PTR = NULL

Write OVERFLOW
Go to Step 7
[END OF IF]

Step 2: SET NEW_NODE = PTR
Step 3: SET PTR = PTR → NEXT
Step 4: SET NEW_NODE → DATA = VAL
Step 5: SET NEW_NODE → NEXT = HEAD
Step 6: SET HEAD = NEW_NODE
Step 7: EXIT

Insertion in singly linked list at beginning

C Function

#include<stdio.h>
#include<stdlib.h>
void beginsert(int);
struct node
{
	int data;
	struct node *next;
};
struct node *head;
void main ()
{
	int choice,item;
	do 
	{
		printf("\nEnter the item which you want to insert?\n");
		scanf("%d",&item);
		beginsert(item);
		printf("\nPress 0 to insert more ?\n");
		scanf("%d",&choice);
	}while(choice == 0);
}
void beginsert(int item)
	{
		struct node *ptr = (struct node *)malloc(sizeof(struct node *));
		if(ptr == NULL)
		{
			printf("\nOVERFLOW\n");
		}
		else
		{
			ptr->data = item;
			ptr->next = head;
			head = ptr;
			printf("\nNode inserted\n");
		}
		
	}

Output

Enter the item which you want to insert?
12

Node inserted

Press 0 to insert more ?
0

Enter the item which you want to insert?
23

Node inserted

Press 0 to insert more ?
2

Next Topic#

← prev next →