Answer to Question #273631 in C++ for Roe

Question

Note: No global declarations

Call the functions in main through menu

Implement the following :

Circular singlyLinked List with following functions :

1)insert_at_head(node* & head, int val);

2)insert_at_tail(node* & head, int val);

3)display(node* head) ;

4)insert_at_pos(node* & head, int val,int pos);

5)delete_at_head(node* & head);

6)delete_at_tail(node* & head);

7)delete_at_pos(node* & head, int pos)

Answer 1

#include<iostream>
using namespace std;


struct node
{
	int item;
	struct node *nextNode;
};


struct node *insert(struct node *head, int data)
{
	
	if (head != NULL)
	return head;


	
	struct node *tempNode =	(struct node*)malloc(sizeof(struct node));


	
	tempNode -> item = data;
	head = tempNode;


	
	head -> nextNode = head;


	return head;
}


struct node *insert_at_head(struct node *head, int data)
{
	if (head == NULL)
		return insert(head, data);


	struct node *tempNode =	(struct node *)malloc(sizeof(struct node));


	tempNode -> item = data;
	tempNode -> nextNode = head -> nextNode;
	head -> nextNode = tempNode;


	return head;
}


struct node *insert_at_tail(struct node *head, int data)
{
	if (head == NULL)
		return insert(head, data);
	
	struct node *tempNode = (struct node *)malloc(sizeof(struct node));


	tempNode -> item = data;
	tempNode -> nextNode = head -> nextNode;
	head -> nextNode = tempNode;
	head = tempNode;


	return head;
}


struct node *insert_at_pos(struct node *head, int val, int pos)
{
	if (head == NULL)
		return NULL;


	struct node *tempNode, *pNode;
	pNode = head -> nextNode;
	do
	{
		if (pNode ->item == val)
		{
			tempNode = (struct node *)malloc(sizeof(struct node));
			tempNode -> item = val;
			tempNode -> nextNode = pNode -> nextNode;
			pNode -> nextNode = tempNode;


			if (pNode == head)
				head = tempNode;
			return head;
		}
		pNode = pNode -> nextNode;
	} while(pNode != head -> nextNode);


	cout <<head-> item << " Not Found." << endl;
	return head;


}
void display(node* head) {
	while(head !=NULL){
		cout<<head->item<<"  ";
		head = head->nextNode;
	}
}
int main()
{
	struct Node *head = NULL;


	head = insert(head, 6);
	head = insert_at_head(head, 4);
	head = insert_at_head(head, 2);
	head = insert_at_tail(head, 8);
	head = insert_at_tail(head, 12);
	head = insert_at_pos(head, 10, 8);


	display(head);


	return 0;
}