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Getter Method for Array Objects  RSS feed

 
Greenhorn
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Hello all,

New to programming so I hope no silly questions! I'm trying to create a very simple game that comprises of a Circle class that defines the x , y coordinates along with some getter and setter methods. I have another class called TheCircles which defines a number of Circle objects to be stored in an array. I have other classes like a game engine but I don't think that's relevant. All I'm trying to do is create a method getCircle that returns a reference to a specific Circle in the array according to the parameter. So a call to getCircle(6) should return a reference to the seventh circle in the array. Does anyone know how I could this?

This is how I'm trying to call getCircle() from main.


And this is part of TheCircles class with the getCircle method.


 
Ranch Hand
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Welcome to the ranch Rachel. The way I see it, you are already doing it correctly. The getter method is returning the (i)th element. The return type should be Circle and not an array of circles , Circle [] because you are supposed to return a single Circle object. At least that is how you have described your use case.
 
Rachell Zammit
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Hi thanks for the reply and the warm welcome

I deleted the [] in the return type of the getCircles method, however when I try running a Junit test in Eclipse a null pointer exception is being made. Any ideas where I'm going wrong?

The unit test.



 
Bartender
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Your constructor creates an array or Circle references, but it does not create any Circle objects. When an array is created, all its elements are initially 0, false, or null, depending on the type of the array. So you either need to create Circles and put them into the array in your TheCircles constructor, or you need to do it separately after you create the TheCircles instance.
 
Rachell Zammit
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That makes sense! Thank you that's what needed to be done

 
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