#include <iostream>
#include <list>
#include <boost/any.hpp>

class tree {
public:
	virtual void grow() = 0;
};

class oak : public tree {
public:
	void grow() {
		std::cout << "oak grows slowly" << std::endl;
	}
};

class pine : public tree {
public:
	virtual void grow() {
		std::cout << "pine grows quickly" << std::endl;
	}
};

int main(int argc, char* argv[]) {
	
	std::list< boost::any > forest;
	forest.push_back(oak());
	forest.push_back(pine());
	
	for(std::list< boost::any >::iterator iter = forest.begin();
		forest.end() != iter; ++iter) {
		iter->grow(); /* this dosen't work */
	}
	
	return 0;
}