Converting a pointer for a base class into an inherited class
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by Shawn B
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Published on 2010-03-26T14:31:00Z
Indexed on
2010/03/26
14:33 UTC
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Hey,
I'm working on a small roguelike game, and for any object/"thing" that is not a part of the map is based off an XEntity class. There are several classes that depend on it, such as XPlayer, XItem, and XMonster.
My problem is, that I want to convert a pointer from XEntity to XItem when I know that an object is in item. The sample code I am using to pick up an item is this, it is when a different entity picks up an item it is standing over.
void XEntity::PickupItem()
{
XEntity *Ent = MapList; // Start of a linked list
while(true)
{
if(Ent == NULL) { break; }
if(Ent->Flags & ENT_ITEM)
{
Ent->RemoveEntity(); // Unlink from the map's linked list
XItem *Item = Ent // Problem is here, type-safety
// Code to link into inventory is here
break;
}
Ent = Ent->MapList;
}
}
My first thought was to create a method in XEntity that returns itself as an XItem pointer, but it creates circular dependencies that are unresolvable.
I'm pretty stumped about this one. Any help is greatly appreciated.
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