Custom simple list implementation

list.hpp

#ifndef LIST_H_
#define LIST_H_

#include <cstddef>

template <typename T>
class List {

	struct item {
		T value;
		item* next;
	};

	item *head;
	item *last;
	int value_count;

public:
	class iterator {
		item *current;

	public:
		iterator& operator=(item* addr) {
			this->current = addr;
			return *this;
		}

		bool operator!=(item* addr) const {
			return (current != addr);
		}

		void operator++() {
			current = current->next;
		}

		void operator++(int dummy) {
			current = current->next;
		}

		T operator*() const {
			return current->value;
		}
	};

	List() :value_count(0) {
		head = new item;
		head->next = NULL;
		last = head;
	}

	item* begin() {
		return head->next;
	}

	item* end() {
		return NULL;
	}

	int size() {
		return value_count;
	}

	void push_back(T value) {
		value_count++;
		item *new_item = new item;
		new_item->value = value;
		new_item->next = NULL;
		last->next = new_item;
		last = new_item;
	}

	void clear() {
		item *first = begin();
		item *next;

		while (first) {
			next = first->next;
			delete first;
			first = next;
		}
		
		head->next = NULL;
		last = head;		

		value_count = 0;
	}

	~List() {
		clear();
		delete head;
	}

};

#endif /* LIST_H_ */