Insertion at Beginning(Front) in CSLL

Front Insertion of node is very easy in Circular Singly Linked List(CSLL). we have to apply some basic node arrangement.

• First we need one new node for inserting, So allocate the memory for new node.
• and then insert the new node at beginning of CSLL.

Working Process

We can implement front operation in CSLL by two ways :
1- Using Only HeadPointer.
2- Using HeadPointer and TailPointer.

• 1- Using Only HeadPointer :

---

• 2- Using HeadPointer and TailPointer :

Code Implementation

As per the working process ,we can also code it by two ways :
1- Code Implementation for Using Only HeadPointer.
2- Code Implementation for Using HeadPointer and TailPointer.

• 1- Code Implementation for Using Only HeadPointer :

                        /*Using HeadPointer Only*/
#include <stdio.h>
#include <iostream>
#include<conio.h>
#include<math.h>
#include<stdlib.h>
struct CreateNode   // Node Structure Initialization
{
	int  data;          // for data element
	struct CreateNode* nextNode;   //for storing the address of next element
};
struct CreateNode *HeadPointer = NULL;    // Initialization of HeadPointer

void insertNodeAtFrontInCSLL(int data)   // Method of front Addition
{
	//Memory Initialization for NewNode
	struct CreateNode* NewNode = (struct CreateNode *)malloc(sizeof(struct CreateNode *));
	struct CreateNode* Temp = NULL;
	Temp = HeadPointer;
	if (NewNode != NULL)
	{
		if (HeadPointer == NULL)
		{
			NewNode->data = data;
			HeadPointer = NewNode;
			NewNode->nextNode = HeadPointer;
			printf("NewNode has been added...\n");
		}
		else
		{
			while (Temp->nextNode!= HeadPointer)
			{
				Temp = Temp->nextNode;
			}
			NewNode->data = data;
			NewNode->nextNode = HeadPointer;
			HeadPointer = NewNode;
			Temp->nextNode = HeadPointer;
			printf("NewNode has been added...\n");
		}
	}
	else
	{
		printf("Memory is not Initialized for NewNode.");
	}
}
int main()
{
	int data, choice;
	do
	{
		printf("Enter the data for insertion :");
		std::cin >> data;
		insertNodeAtFrontInCSLL(data);
		printf("Press 0 for more insertion :");
		std::cin >> choice;
	} while (choice == 0);
	struct CreateNode* Temp = HeadPointer;
	printf("Node data after insertion process :\n");
	while (Temp->nextNode!=HeadPointer )
	{
		printf("%d ", Temp->data);
		Temp = Temp->nextNode;
	}
	printf("%d ", Temp->data);
	_getch();
	return 0;
}

• 2- Code Implementation for Using HeadPointer and TailPointer :

                        /*Using HeadPointer and TailPointer*/
#include <stdio.h>
#include <iostream>
#include<conio.h>
#include<math.h>
#include<stdlib.h>
struct CreateNode   // Node Structure Initialization
{
	int  data;          // for data element
	struct CreateNode* nextNode;   //for storing the address of next element
};
struct CreateNode *HeadPointer = NULL;    // Initialization of HeadPointer
struct CreateNode *TailPointer = NULL;    // Initialization of TailPointer

void insertNodeAtFrontInCSLL(int data)   // Method of front Addition
{
	//Memory Initialization for NewNode
	struct CreateNode* NewNode = (struct CreateNode *)malloc(sizeof(struct CreateNode *));

	if (NewNode != NULL)
	{
		if (HeadPointer == NULL || TailPointer == NULL)
		{
			NewNode->data = data;
			NewNode->nextNode = NULL;
			HeadPointer = NewNode;
			TailPointer = HeadPointer;
			printf("NewNode has been added...\n");
		}
		else
		{
			NewNode->data = data;
			NewNode->nextNode = HeadPointer;
			HeadPointer = NewNode;
			TailPointer->nextNode = HeadPointer;
			printf("NewNode has been added...\n");
		}
	}
	else
	{
		printf("Memory is not Initialized for NewNode.");
	}
}
int main()
{
	int data, choice;
	do
	{
		printf("Enter the data for insertion :");
		std::cin >> data;
		insertNodeAtFrontInCSLL(data);
		printf("Press 0 for more insertion :");
		std::cin >> choice;
	} while (choice == 0);

	printf("Node data after insertion process :\n");
	struct CreateNode *Temp = HeadPointer;
	while (Temp != TailPointer)
	{
		printf("%d ", Temp->data);
		Temp = Temp->nextNode;
	}
	printf("%d ", Temp->data);
	_getch();
	return 0;
}

Time & Space Complexity

• When we use HeaderPointer Only then Time Complexity will be O(n).
• When we use HeaderPointer and also TailPointer then Time Complexity will be O(1).
• Space Complexity will be O(1).