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Add an object to Array of Objects

Matt Wilde
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Joined: Feb 27, 2012
Posts: 34
So i have a class ElectronicDevice.
I have another class SurgeProtector.

In surge protector i have
ElectronicDevice[] ED = new ElectronicDevice[20];

In surge protector i have a method

public boolean addDevice (ElectronicDevice e){
return true; //return false if nothing added
}

in the addDevice method how do i add an ElectronicDevice e to the array ED?
Winston Gutkowski
Bartender

Joined: Mar 17, 2011
Posts: 8427
    
  23

Matt Wilde wrote:in the addDevice method how do i add an ElectronicDevice e to the array ED?

You can't as it stands because you need to provide an index. Either that, or you need to keep a 'current index' to the array somewhere else.

Personally, I'd have a look at ArrayList. That, you can add to.

Winston


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Ryan Sykes
Ranch Hand

Joined: Jan 18, 2012
Posts: 58
Matt, you will probably want to have an int instance variable in SurgeProtector, like int lastIndex, that keeps track of the lastIndex of the elements inserted into the array. Use that index value to add an element to the array and then increment lastIndex by 1. I'd recommend looking at the ArrayList source code in Java. I always find it fun to see how things are implemented and you can learn quite a bit. ArrayList essentially consists of an internal array, that is dynamically resized (rather, duplicated) when the size of the ArrayList exceeds the initial size of the internal array representation.
Matt Wilde
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Joined: Feb 27, 2012
Posts: 34
Got it! Thanks so much guys I'll get to work!
 
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