What is the equivalence to List<Object> in Java for C++?

Do I use std::vector<void *>?
Thanks
Jack

No, you change your design such that you don't need a god-object.

The equivalence is std::list<myBaseObjectClass&>

but there is probably a better design approach altogether.

I better off redesign my program. Let me have a good thought about it
Thanks
Jack

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Originally Posted by lucky6969b

Do I use std::vector<void *>?

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List in Java is an interface. The two most common concrete implementations of List are ArrayList and LinkedList. The first corresponds with std::vector and the second with std::list.

The notion of a top class doesn't exist in C++ but one could think of void being such a class and then void* is pretty close to a reference to Object in Java (although void doesn't have any methods).

So std::vector<void*> of C++ corresponds very well with ArrayList<Object> of Java.

Anyone writing code that uses std::vector<void*> (or std::list<void*> or anything like this) that comes across my desk had better keep walking towards the exit.:thumbd:

As others have correctly pointed out, this is a design problem which needs to be re-thought.

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Originally Posted by 2kaud

that comes across my desk

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Do they have desks at McDonalds now? Is it to raise the status of burger flipping? Just kidding, but you're jumping to conclusions. Did you see a design? No? So how can it be bad?

There's nothing inherently wrong with std::vector<void*>. That, or something similar, is what you can expect to find in low level C++ designs when you can't or don't want to make assumptions about type.

Maybe the OP realized he couldn't access hardware in Java and is now looking to do it in C++. And up pops a bunch of besserwissers yelling bad design. Lucky you to have a desk to hide your red face under. :)

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Originally Posted by razzle

Is it to raise the status of burg
There's nothing inherently wrong with std::vector<void*>

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Nothing wrong with it other than turning something most likely caught by a compiler into a runtime error. Unless you're used to program C with classes, you can restructure to get rid of the void*.

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Originally Posted by Arjay

Nothing wrong with it other than turning something most likely caught by a compiler into a runtime error. Unless you're used to program C with classes, you can restructure to get rid of the void*.

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And sometimes even if you're used to object oriented C++ no amount of restructuring can factor out a downcast. You simply have to deal with "a pointer to an unknown type" (the C++ Programming Language 4'th ed. by Stroustrup p. 172).

Lets face it, C++ is a versatile language and one of its strengts is that it allows you to program without contraceptives (at your own discression). Otherwise why don't we all switch to Java?

--- doubleposting by mistake ---

I agree that use of a void* pointer is sometimes useful and sometimes cannot be avoided. The point I was making clumsily (after a bad day :eek:) was that I wouldn't expect to see containers/arrays of this type.

PS McDonalds do a good medium-rare flame war :D - and no, I couldn't hide under the desk as there's too much kit there.

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Originally Posted by razzle

And sometimes even if you're used to object oriented C++ no amount of restructuring can factor out a downcast. You simply have to deal with "a pointer to an unknown type" (the C++ Programming Language 4'th ed. by Stroustrup p. 172).

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Sure, there are always rare cases, but most times you need a pointer to an unknown type about as often as you need a goto. For some, that's more frequently than others.

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Originally Posted by Arjay

Sure, there are always rare cases, but most times you need a pointer to an unknown type about as often as you need a goto. For some, that's more frequently than others.

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You're allowing yourself a superior and condescending tone.

If you're such a genious why don't you enlighten us mere mortals as to why anyone should select C++ over Java if it isn't for the versatility of the former (and legacy is no issue)?

And does your oppsition to goto also include break in loops and return not at the end of functions? Should these also be used as rarely as void* in your view?

And while you're at it. What would you suggest to better correspond to ArrayList<Object> than std::vector<void*> ?

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Originally Posted by razzle

You're allowing yourself a superior and condescending tone.

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I only use that tone when working at McDonald's - a nod toward your previous superior and condescending comment:

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Do they have desks at McDonalds now? Is it to raise the status of burger flipping?

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Btw, ever notice the irony of folks that condescendingly refer to others as geniuses often misspell the word when doing so?

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Originally Posted by razzle

So std::vector<void*> of C++ corresponds very well with ArrayList<Object> of Java.

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It does, except that primitive types in java do not derive from Object, and would have to be wrapped.
If void* was God, then Object would be no better than Jesus I guess.