On Tue, 10 Apr 2012 03:41:28 -0400, CrudOMatic <[email protected]>
wrote:
The D documentation is a little lacking in a lot of areas. I'm needing
to know an exact way of making arrays of objects.
For example:
/* Deck class */
// Will be adjusted with the proper cards for each game type
class Deck {
/* Card count - used to keep track of how many cards are left in the
deck - when zero, Deck is discarded from the Shoe */
int cardCount;
/* Cards array - initialized to cardCount elements */
Card cards[];
/* Constructor */
this(int no_cards) {
cardCount = no_cards;
cards = new Card[cardCount];
}
/* Destructor */
~this() {
delete cards;
}
}
I want to stop you right there. *DON'T* use a destructor here, you will
have issues, mostly of the random segfault nature.
Quickly explained, if the Deck class and it's cards array are destroyed at
the same time in the GC, there is no guarantee that the cards array is
valid when you try to destroy it.
Destructors are strictly for cleaning up resources that *AREN'T* allocated
by the GC. For example anything created with C's malloc, or an open file
descriptor, etc.
the cards[] array is meant to be an array of Card objects, and I'm
initializing it in the constructor as seen above. This hasn't been
tested yet, but I'm needing to know if this is the correct way of doing
it - to save headaches later.
This is fine. Note that D slices (what cards[] is) contain a length
member, so no need to store an extra member.
Also, while I'm here, how would you go about moving objects from the
cards array in the Deck class to another class containing a cards array
- I'm talking about MOVING them, not COPYING them. I don't want any
issues with references being destroyed after being moved to another
class when I happen to destroy an instance of the Deck class.
All classes are references (i.e. an element of cards is a single pointer
to a Card instance). There is no need to move them, as a straight copy is
just copying the reference. And since you have removed the dtor, there
should be no worry about accidentally destroying the cards ;)
You really should read the spec page on classes
(http://dlang.org/class.html) and I highly recommend picking up the D
programming language book.
-Steve
