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mutually recursive classes

Started by UK_Gamer May 8, 2004 at 9:04 AM 4 replies 450+ views

Original Post

May 8, 2004 at 9:04 AM

Hi, I have successfully implemented a basic A* search program in Java, and am now trying to port it to C++. The problem is my node and nodelist classes in java. Node class holds the data at that node, and a nodelist of nodes connected to this node. Nodelist class holds a nodelist of nodes connected to this list, as well as the node at the top of this list. Having two classes use each other is fine in java, but in C++, one class can''t compile until the other one is compiled, and vice-versa. Is there a way round this problem?

Greg K

May 8, 2004 at 9:07 AM

Yes.

class NodeList;

class Node
{
...
};

class NodeList
{
...
};

psykr

May 8, 2004 at 12:55 PM

Forward declarations only work if you''re using pointers, or otherwise don''t need the actual definition of the class, only the name.

Zahlman

257

Zahlman

May 8, 2004 at 5:34 PM

Yes, but he needs to be using a pointer in at least one of the classes anyway.

Thunder_Hawk

May 8, 2004 at 5:57 PM

quote:
Original post by psykr
Forward declarations only work if you''re using pointers, or otherwise don''t need the actual definition of the class, only the name.

For it to be logically possible (realizing that we don''t use quantum computers) for it to work in any language (he said it worked in java) one of the classes must be restricted to merely having a pointer to the other.

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UK_Gamer

Author

UK_Gamer

May 9, 2004 at 6:30 AM

Pointers are the solution thanks.

(Java only uses pointers I believe which is why it worked originally)

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