#include <iostream>
#include <cstring>

class StringIterator
{
	const char *position, *end;
public:
	StringIterator(const char * str) : 
		position(str), 
		end(str + strlen(str))  { }
	bool at_end() const { return position == end; }
	void advance() { ++position; }
	char get_char() const { return *position; }
};

void hello_world(StringIterator & iterator)
{
	for(StringIterator i=iterator; !i.at_end(); i.advance())
	{
		std::cout << i.get_char();
	}
}

int main()
{
	StringIterator iterator("Hello world!\n");
	hello_world(iterator);
	return 0;
}