Linked List Demo

LList.cpp

//Linked List Demo
#include <iostream>
using namespace std;

template <typename T>
class LList{
public:

	struct Node{
		T data;
		Node *next;
	};

	Node *head;
	Node *tail;

	LList(){
		head = NULL;
		tail = NULL;
	}

	~LList(){
		Node *n = head;

		while (n != NULL){
			n = n->next;
			delete(head);
			head = n;
		}
	}

	const void add_node(T data){
		Node *n = new Node();

		n->data = data;
		n->next = NULL;

		if (head == NULL){
			head = n;
			tail = n;
			n = NULL;
		}
		else{
			tail->next = n;
			tail = n;
		}
	}

	const void InsertFirst(T data){
		Node *n = new Node();
		n->data = data;
		n->next = head;
		head = n;
	}

	const void InsertLast(T data){
		add_node(data);
	}

	const void InsertAt(int index, T data){
		size_t x = 0;

		Node * cur = head;
		Node *temp = new Node();
		Node *pre = new Node();

		if (head == NULL){
			return;
		}

		while (x < index){
			pre = cur;
			cur = cur->next;
			x++;
		}
		temp->data = data;
		pre->next = temp;
		temp->next = cur;
	}

	const void delete_first(void){
		if (head != NULL){
			Node *n = head;
			head = head->next;
			delete(n);
		}
	}

	const void delete_last(void){
		Node *cur;
		Node *prev = new Node();

		cur = head;

		while (cur->next != NULL)
		{
			prev = cur;
			cur = cur->next;
		}

		tail = prev;
		prev->next = NULL;
		delete(cur);
	}

	const void deleteByIndex(int index){
		Node *cur = head;
		size_t x = 0;
		Node *prev = new Node();

		while (x < index){
			prev = cur;
			cur = cur->next;
			x++;
		}
		prev->next = cur->next;
	}

	Node* find(T data){
		Node *n = head;
		bool found = false;

		if (head != NULL){
			while (n != NULL){
				if (n->data == data){
					found = true;
					break;
				}
				n = n->next;
			}
		}
		return n;
	}

	const void destroy_nodes(void){
		Node *n = head;

		while (n != NULL){
			n = n->next;
			delete(head);
			head = n;
		}
	}

	const size_t size() const{
		Node *n = head;
		size_t x = 0;

		while (n != NULL){
			x++;
			n = n->next;
		}

		return x;
	}

	const void display_nodes(void){
		Node *n = head;

		while (n != NULL){
			std::cout << n->data << std::endl;
			n = n->next;
		}
	}
};

int main(){
	LList<int> nums;
	LList<int>::Node *f;

	nums.add_node(10);
	nums.add_node(20);
	nums.add_node(30);
	nums.add_node(40);

	nums.deleteByIndex(2);

	nums.display_nodes();

	f = nums.find(40);

	if (f != NULL){
		std::cout << f->data << " was found." << std::endl;
	}
	
	std::cout << std::endl;
	nums.InsertFirst(60);
	nums.InsertLast(255);

	nums.display_nodes();

	system("pause");
	return EXIT_SUCCESS;
}