#include <stdio.h>

template<typename T>
class List {
public:
	struct Node {
		Node* next;
		T info;
	};
	class Iterator {
	private:
		Node* current;
	public:
		explicit Iterator(Node* c) {
			current = c;
		}
		T& operator*() const {
			return current->info;
		}
		T* operator->() const {
			return &current->info;
		}
		void operator++() {
			current = current->next;
		}
		bool isValid() const {
			return current != nullptr;
		}
	};
private:
	Node* first;
	Node** pLast;
	
public:
	List() {
		first = nullptr;
		pLast = &first;
	}
	
	void add(T val) {
		*pLast = new Node;
		(*pLast)->next = nullptr;
		(*pLast)->info = val;
		pLast = &(*pLast)->next;
	}
	bool isEmpty() const {
		return first == nullptr;
	}
	Iterator iterator() {
		return Iterator(first);
	}
};

int main()
{
	List<int> list;
	list.add(10);
	list.add(12);
	list.add(42);

	for(List<int>::Iterator it=list.iterator() ; it.isValid() ; ++it) {
		*it = *it * 10;
	}

	printf("Begin list\n");
	for(List<int>::Iterator it=list.iterator() ; it.isValid() ; ++it) {
		printf("  %d\n", *it);
	}
	printf("End list\n");
}