circular linked list deletion.cpp

#include<iostream>
using namespace std;
class node{
public:
	int data;
	node *next;
	
	node(int d){
		data=d;
		next=NULL;
	}
};
void insertion_at_head(node *&head,int data){
	//1.create a new node
	node *n=new node(data);
	node *temp=head;
    n->next=head;
	//2.if list is not empty than traverse the list till last node and updat the pointer of last node to the new node
	if(temp!=NULL){
		while(temp->next!=head){
			
			temp=temp->next;
		}
		temp->next=n;
	}
	//if list is empty then new node poins to itself
	else{
		n->next=n;
	}
	//update head to new node
	head=n;
}
void print(node *head){
	node *temp=head;
	while(temp->next!=head){
		cout<<temp->data<<"  ";
		temp=temp->next;
	}
	cout<<temp->data<<"  ";
}
//search function
node * search(node *head,int data){
	node *temp=head;
	while(temp->next!=head){
		if(temp->data==data){
			return temp;
		}
		temp=temp->next;
	}
	//for last node
	if(temp->data==data){
		return temp;
	}
	return NULL;
}
//delete function
void delete_node(node *&head,int data){
	node *del=search(head,data);
	//if node is not present
	if(del==NULL){
		return;
	}
	//if del(node to be deleted) is head node
	if(head==del){
		head=head->next;
	}
	//if del is present
	node *temp=head;
	//go till one step before of del
	while(temp->next!=del){
		temp=temp->next;
	}
	temp->next=del->next;
	delete del;
}

int main(){
	node *head=NULL;
	insertion_at_head(head,1);
	insertion_at_head(head,2);
	insertion_at_head(head,3);
	insertion_at_head(head,4);
	print(head);
	cout<<endl;
	
	delete_node(head,3);
	print(head);
	cout<<endl;
	
	
	delete_node(head,1);
	print(head);
	return 0;
}