#include <string>
#include <iostream>
#include <map>
#include <vector>

using namespace std;

class Node { //abstract base class
	public:
		virtual string get_name() = 0; //signal output
};

class A_node: public Node {
	public:
		string get_name(){ return "A"; };
		string get_occupation(){ return "an A"; };
};

class B_node: public Node {
	public:
		string get_name(){ return "B"; };
		string get_occupation(){ return "a B"; };
};

class C_node: public Node {
	public:
		string get_name(){ return "C"; };
		string get_occupation(){ return "a C"; };
};

class Node_factory {
	public:
		template <typename T>
		T* clone(T* proto) {
			return new T();
		};
		Node_factory() {
			add_type("A",new A_node());
			add_type("B",new B_node());
			add_type("C",new C_node());
		}
		Node *get_node(string type) {
			if (type=="A") return new A_node();
			if (type=="B") return new B_node();
			if (type=="C") return new C_node();
		};
		map<string,Node*> type_map;
		void add_type(string type,Node *proto){
			type_map[type]=proto;
		};
		Node *create(string type) {
			if (type_map.find(type)!=type_map.end()) {
				return (Node*)clone(type_map[type]);
			}
		}
};

int main() {
	Node_factory f=Node_factory();
	vector<Node*> nodes;
	nodes.push_back(f.get_node("A"));
	nodes.push_back(f.get_node("B"));
	nodes.push_back(f.get_node("C"));
	for (auto &i: nodes) {
		cout << i->get_name() << endl;
	}
}