Merge two unsorted linked list

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

struct node {
	int data;
	node* next;
};

void setData(node* head)
{
	node* tmp;

	tmp = head;

	while (tmp != NULL) {

		cout << tmp->data
			<< " -> ";
		tmp = tmp->next;
	}
}
node* getData(node* head, int num)
{

	node* temp = new node;
	node* tail = head;

	temp->data = num;
	temp->next = NULL;

	if (head == NULL) {
		head = temp;
		tail = temp;
	}

	else {

		while (tail != NULL) {

			if (tail->next == NULL) {
				tail->next = temp;
				tail = tail->next;
			}
			tail = tail->next;
		}
	}

	return head;
}

node* mergelists(node** head1,
				node** head2)
{

	node* tail = *head1;

	while (tail != NULL) {

		if (tail->next == NULL
			&& head2 != NULL) {
			tail->next = *head2;
			break;
		}
		tail = tail->next;
	}

	return *head1;
}

void sortlist(node** head1)
{
	node* curr = *head1;
	node* temp = *head1;
	while (curr->next != NULL) {

		temp = curr->next;
		while (temp != NULL) {

			if (temp->data < curr->data) {
				int t = temp->data;
				temp->data = curr->data;
				curr->data = t;
			}
			temp = temp->next;
		}
		curr = curr->next;
	}
}

int main()
{
	node* head1 = new node;
	node* head2 = new node;

	head1 = NULL;
	head2 = NULL;

	// Given Linked List 1
	head1 = getData(head1, 4);
	head1 = getData(head1, 7);
	head1 = getData(head1, 5);

	// Given Linked List 2
	head2 = getData(head2, 2);
	head2 = getData(head2, 1);
	head2 = getData(head2, 8);
	head2 = getData(head2, 1);

	// Merge the two lists
	// in a single list
	head1 = mergelists(&head1,
					&head2);

	// Sort the unsorted merged list
	sortlist(&head1);

	setData(head1);
	return 0;
}