Comparing polymorphic types

[Leano]

I have created an abstract type (call it base), and several inherited types (child1..n). I then created an array of base classes.

I have used this array to store instances of each of the child classes. This all works fine, but I would like to be able to see which one of the child classes is stored in each element of the array. I have tried using the typeid() function, but that comes up with a warning that it can't be used with polymorphic types!

I could always just add another atribute to the base class that says which one of the child classes it was using, but I am reluctant to do this, purley becasue it seems like a bit of a cop-out! I have also tried messing around with pointers (array of pointers to base class) without any luck! Any ideas?

[Unregistered]

You could use something called RTTI - Run Time Type Identification. Use the dynamic_cast operator to get it work.

subclass *p = dynamic_cast <subclass *> (baseclass);
if (p)
   some code here..... //its a pointer to subclass
else
   some code here ....//not a pointer to subclass

They say that using RTTI is often a sign of bad "codning" (sorry) and insteed of RTTI consider using virtual functions and multiple inheritance insteed.

[Sebastiani]

If the bytecount of each structure of the subclasses is different you may be able to use the sizeof() operator. Not very classy, but it may work:

if(subClassArr[x] == sizeof(someSubclass) )
....etc