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Index › Programming Questions & Help › Syntax Questions › Inheritance Problem
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Inheritance Problem (Read 1453 times)
Laani
Inheritance Problem
May 29th, 2010, 9:03pm  
Hi, I was wondering if someone might be able to explain this to me.

I have a 'Content' Class which has two sub classes: 'ContentImage', 'ContentMovie'.

I have an array of type 'Content' which contains both types of the sub classes.

Both the sub classes have the method 'getContent', which returns either an Image or a Movie. However, when I run the program it doesn't recognise the 'getContent' method.

I think I'm going wrong when I'm getting the 'Content' object from the array and trying to use a sub class method. If this is the case, how would I tell it which type it is??

In advance. Thank you for the help
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PhiLho 
Re: Inheritance Problem
Reply #1 - May 30th, 2010, 12:53am  
It is hard to answer without seeing some code structure...
But well, from your description, I think Content must be abstract, ie. you probably will never do something like new Content();
And it must define a method, perhaps abstract itself (without code), getContent(). This forces the sub-classes to implement this method, and tells the compiler it can be sure any class of type Content will have this method.

Perhaps this is what you did already, I don't know.
If needed, show your code (you can remove the code in the methods if it is long).
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Smitty
Re: Inheritance Problem
Reply #2 - May 30th, 2010, 1:20pm  
I wonder also: You say that the ContentImage class returns an image from its getContent() method, while the ConentMovie class returns a movie.  Do they return different data types then?  It sounds like it.  If so, they'll be considered two different methods and you'll need to know which subclass you're accessing.

So, there are two or three issues you might be facing; if you could post a little code it would help.
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