#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

class foundation {
public:
	~foundation() {cerr << "destruct the foundation\n";}
};

class walls {
public:
	~walls() {cerr << "destruct the walls\n";}
};

class roof {
public:
	~roof() {cerr << "destruct the roof\n";}
};

//Data types of the exceptions:
class trivial {};  //handling this requires the destruction of only the roof
class medium {};   //requires destruction of roof and walls
class severe {};   //requires destruction of roof, walls, and foundations

void f() throw (severe);
void g() throw (severe, medium);
void h() throw (severe, medium, trivial);

int main()
{
	srand(static_cast<unsigned>(time(0)));

	try {
		f();
	}

	catch (severe) {
		cerr << "main caught a severe exception.\n";
		return EXIT_FAILURE;
	}

	return EXIT_SUCCESS;
}

void f() throw (severe)
{
	foundation found;

	try {
		g();
	}

	catch (medium) {
		cerr << "f caught a medium exception.\n";
	}
}

void g() throw (severe, medium)
{
	walls w;

	try {
		h();
	}

	catch (trivial) {
		cerr << "g caught a trivial exception.\n";
	}

	catch (...) {
		cerr << "g caught a non-trivial exception.\n"
			"Don't worry about having scratched the walls when destructing\n"
			"the roof--we're about to destruct the walls too.\n";
		throw;
	}
}

void h() throw (severe, medium, trivial)
{
	roof r;

	switch (rand() % 3) {
	case 0:
		throw trivial();
		break;

	case 1:
		throw medium();
		break;

	case 2:
		throw severe();
		break;

	default:
		break;
	}
}