#ifndef INTROSPECTH
#define INTROSPECTH
#include <iostream>
using namespace std;

class introspect {
	const introspect *const p;
public:
	introspect(): p(this) {}
	introspect(const introspect&): p(this) {}
	introspect& operator=(const introspect&) {return *this;}

	friend ostream& operator<<(ostream& ost, const introspect& i) {
		return ost << "introspect at address " << &i
			<< " contains " << i.p;
	}

	~introspect() {
		if (p != this) {
			cerr << "Invariant disrupted: " << *this << "\n";
		}
	}
};
#endif