#include <iostream>
#include <cstdlib>

#include "gas.h"
#include "liquid.h"
#include "solid.h"
using namespace std;

int main()
{
	solid ice = 10;
	liquid water = 20;
	gas steam = 30;

	water = ice;   //convert solid to liquid: water = ice.operator liquid();
	steam = water; //convert liquid to gas:   steam = water.operator gas();

	//steam = ice;                      //won't compile
	//steam = static_cast<gas>(ice);    //won't compile
	steam = static_cast<liquid>(ice);   //ice.operator liquid().operator gas();

	return EXIT_SUCCESS;
}