Thread: Default Constructors w/Classes as Parameters

Confusing title, confusing question.
First off, I'm making arrays of type Room (class). I'm aware I have to have default constructor arguments for this to work... or whatever you call it. My problem is, I can't seem to give a default value to one of the parameters in my constructor function; and that parameter type happens to be another class.

The constructor header:

Code:

Room::Room(int dr = 0, int dc = 0,                   // row, column number (d for default arguments)
           bool dN = true, bool dE = true,           // exits (N, E)
           bool dS = true, bool dW = true,           // exits (S, W)
           char* dname = '\0', char* ddescr = '\0',  // name, description
           Monster dmob)

Okay Dokay - since I am creating an array of these Room types, I need default constructor arguments.. and I have them there.. all except for the last parameter (Monster dmob). How can I give this a default value?

If this doesn't make sense please say so, and i'll post the rest of the code.

maybe you could use a pointer to a Monster object and make it NULL in the constructor?

hmm.. that sounds like it will work. but i dont know what any of that means... 'specially that null pointer (i a newb)
Could you explain in a nutshell what that is?
Is it something like this?

Code:

Room::Room(........,Monster* p_Monster = NULL)
{
 // ....
 thePrivateDataMemberOfTypeMonster = *p_Monster;
}

yup, that looks correct

Wow, thanks endo!!

Of course if you are making a default constructor, then you know you can just create one with no arguments right? eg

Code:

Room::Room( )
{
   dr = dc = 0;
   dN = dS = dW = dE = true;
   dname = ddesc = NULL;
   //no need to initialise Monster, its defualt constructor should do that
}

Anyway, its just another idea...

(kind off subject)
*Wants to be as smart as endo some day*
What book do you reccommend for beginners endo? That C++ 21 days seems popular...

I aint that smart, if I was I'd have a programming job

Anyway, I've got "C++ How to Program", third ed - Deitel & Deitel. Thats a good book which seemed really complex when I started but I don't think you'll struggle with it at all. It covers loads of stuff as well, still not read the whole book...

Edit : And it comes with the intro version of Visual C++ 6, which is nice.

Thankyou

Doh. It compiled just fine with no errors, but now when I try to run the .exe, i get illegal operation! *whine*

Is it definitly because of the constructor? post the code.

it is very big.
should i upload it or post it?

Okay here's the whole thing.

The classes are in classes.h

I have errors telling me there is no appropriate default constructor for Room and Monster Objects. I have removed your Monster constructor and put this instead, which doesn't produce errors

Code:

Monster::Monster( )
{
	maxHP = curHP = str = agi = gold = xp = 0;
	alive = false;
	name = art = Art = attack = dodge = NULL;
}

I can fix the whole lot if you like but the Room constructor is going to be very similar, so if this isn't what you want say so now.

For the Room class you will also need to overload the assignment(=) operator for the Monster class because you'll get dodgy results otherwise.

Sounds good to me! I'm always looking for pointers at c++ (not the pointers to addresses)

I'm not quite sure what overloaded assignment is.