Program 4	Dordal		Due: April 22, 2005

You are to modify the game program presented in class, adding the
features below. Every new command should have a "generic" response;
ie be recognized by Room::response(). That is, TURN VALVE in a 
non-ValveRoom should say "There is nothing to turn here!"

Also be aware that in order to get the dynamic_cast operator to work,
you have to enable the run-time type information with the "/GR" option.
Go to Project (on main menubar) 
 	=> Properties (menu item) 
 	=> C/C++ (folder) 
 	=> Language 
 	=> Enable Run-Time Type Info (set to Yes)


1. Add a second Lantern, of class Lantern. The second Lantern should
**have the same name**, LANTERN. When the user invokes the command
	LIGHT LANTERN
you look on the Inventory for the first such object and light() it. 
Note that you will need to downcast from Carryable* to Lightable* to 
do this. Similarly, in the dark rooms, you will need to check whether
there is any Lightable on Inventory (it also has to be lit!). 

The function haslight() may be useful here, though notice that it doesn't 
check whether the lantern is lit. Notice also that, as written, it returns
only the first Lightable, which may be the "wrong" one! Your program, for
example, should work properly even when both LANTERNs are on the
Inventory list and only the second one is lit. 

The two Lantern objects are different instances of the class Lightable.
You are to arrange for there to be some *material* difference, even
when both are lit. In other words, you are to have some puzzle where 
it makes a difference which of the two (identically named!) LANTERNs 
the user has. For example,
	...
	There is a magic inscription at the base, but you'll need to
	shine the light on it to read it.
	
	SHINE LANTERN		// added room-specific verb SHINE
	
	I'm sorry! You seem to have the dim lantern; somewhere there
	is the bright lantern though.
	
Note that if the user has both the dim LANTERN and bright LANTERN on
Inventory, in that order, then LIGHT LANTERN will light only the first,
dim, LANTERN. To light the second lantern, one can do
	DROP LANTERN	// drops first lantern
	LIGHT LANTERN	// lights remaining lantern
	TAKE LANTERN	// picks first lantern back up

It is not forbidden to have an upfront distinction made between the
two lanterns, but they *are* required to have the same name and so
this would make printing bright/dim descriptions rather complicated.
The right way to do this, should you decide to implement this, would
probably to give Carryables both name and description, equal by default
but settable in some cases to different strings. Personally, I wouldn't
bother.


2. If you eat the chocolate, it should go away after 2-3 bites. 
Keep the number of bites left as an attribute of the chocolate itself. 
To do this, you will need to create a
	class Eatable : public Carryable {
	private:	int _bitesleft;
	public:		bool eat() {
				if (!_bitesleft) return false; 
				else _bitesleft --;
			}
or something like that. You don't need downcasting if there is only
one Eatable thing in the game (CHOCOLATE), although downcasting is still
a very reasonable way to implement this.


3. Introduce a puzzle room where you cannot *leave* the room until some
action occurs. Possibilities are:
    You have to FIGHT the dragon (with a SWORD?)
    You have to GIVE the dragon a PRESENT or COOKIE.
    There is a cave-in and you have to DIG (with SHOVEL?)


4. Make the StoneRoom (or whatever room in your game comes after "Passage1")
be "dark"; that is, if the user gets that far without a Lantern then 
they cannot see anything except the way back out (to the north). 
They cannot "move stone", or TAKE anything. StoneRoom::response() should
attempt to prohibit much of anything. 

While it is possible to check for the lantern in on_entry, it is much
better to check as well in each call to response(), in case the user
did DROP LANTERN. 

In principle you want every deep cave room to be "dark", but handling things
like DROP LANTERN make this a little complicated.


5. You are to add one additional puzzle of your own. Your puzzle should,
at a minimum, involve the following:
	one new CarryObj 
	one new verb 
	one new derived room class, with special behavior for 
		at least one verb (new or existing).
	some kind of state change to the room or to an object
	 	(like the stone being moved or valve being turned)
You will be graded in part on the inventiveness of your puzzle.

Here are a few possibilities.

UNLOCK CHEST with a KEY found elsewhere; once the chest is unlocked,
something should be inside.

Cross a rickety two-move bridge over a bottomless pit; if you carry too
much the bridge will break; you can only carry two things at a time.

You need to CAST SPELL in the WizardsChamber, but in order to do this
you must first find in the game a BELL, BOOK, and CANDLE. (And maybe
LIGHT CANDLE? Or maybe, in the simpler direction, just find NEWTEYE 
and BATWING. If you try to CAST SPELL and don't have the ingredients,
the game should tell you what you're missing.)

The different-Lanterns issue in #1 can be a part of one of the puzzles 
required in parts 3 and 5. The puzzles in 3 and 5 should be relatively
independent of one another, though.