A conceptual question on using DLL'd

Hello, I have been started using dll's with classes, and I have find that there's two ways to use them (I don't know if there's more that two); the first is a simple call from the main program like that:

Code:

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CTest A;
printf("%d",A.someFunction());
}

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seems like a call to a struct variable. It works well, althought the 'someFunction()' only returns an int value. But I tryed to do it by the habitual way of working with classes and also works well, seems like there's no difference on the results; that second method I call a constructor and a destructor for the class, something like:

Code:

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CTest* A;
A=new CTest();
printf("%d",A->someFunction());
delete A;

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of course in that second way I have declared the constructor and destructor in the dll class, but I have to modify it a bit: if I declare it as:

Code:

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virtual ~CTest();

---

it makes a big error on the call to the 'delete A', but if I declare it as non_virtual (simply '~CTest();') there's no error, and works fine.

And that's my question: both methods (the first without constructor/destructor and the last with constructor/non_virtual_destructor) are valid ways to use classes with dll's?

Thank's in advance
Niara

(hello, a little error on the question title, at the end please read "dll's" instead "dll'd")
Niara