Thread: How does RTTI work?

Hi, just wrote this simple program:

Code:

#include <iostream>
using namespace std;

class base {
public:
	virtual ~base() {}
	virtual void print() {
		cout << "base" << endl;
	}
};

class derived : public base {
public:
	void print() {
		cout << "derived" << endl;
	}
};

void print(base* ptr) {
	ptr->print();
}

int main() {
	base *base_ptr = dynamic_cast<base*>(new derived);
	print(base_ptr);
	system("PAUSE");
}

and the program writes "derived" in the terminal. This is what's called run time type information (RTTI) I guess, since the print function have no way, when compiling, to know wheather ptr is really a base* or not. So how can it determine which type ptr is of in runtime? Information about which type ptr is has to be stored somewhere (hasn't it), but where?