Find pairs with given sum in doubly linked list.cpp

#include<bits/stdc++.h> 
using namespace std; 


struct Node 
{ 
	int data; 
	struct Node *next, *prev; 
}; 

 
void pairSum(struct Node *head, int x) 
{ 

	struct Node *first = head; 
	struct Node *second = head; 
	while (second->next != NULL) 
		second = second->next; 

	bool found = false; 
 
	while (first != second && second->next != first) 
	{ 
	
		if ((first->data + second->data) == x) 
		{ 
			found = true; 
			cout << "(" << first->data<< ", "
				<< second->data << ")" << endl; 

			
			first = first->next; 
 
			second = second->prev; 
		} 
		else
		{ 
			if ((first->data + second->data) < x) 
				first = first->next; 
			else
				second = second->prev; 
		} 
	} 
 
	if (found == false) 
		cout << "No pair found"; 
} 

void insert(struct Node **head, int data) 
{ 
	struct Node *temp = new Node; 
	temp->data = data; 
	temp->next = temp->prev = NULL; 
	if (!(*head)) 
		(*head) = temp; 
	else
	{ 
		temp->next = *head; 
		(*head)->prev = temp; 
		(*head) = temp; 
	} 
} 


int main() 
{ 
	struct Node *head = NULL; 
	insert(&head, 9); 
	insert(&head, 8); 
	insert(&head, 6); 
	insert(&head, 5); 
	insert(&head, 4); 
	insert(&head, 2); 
	insert(&head, 1); 
	int x = 7; 

	pairSum(head, x); 

	return 0; 
}