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Arrays

I have a couple of questions with arrays:

1) if I setup and array like this so:
         public static string[] nameArray = { "Greg" };
    Is that array able to grow beyond that one? In other words can I add additional names to the array?  or do I have to define a size?  

Guess I am just confused and trying to understand them.

2) I am creating a function to reset the apps variable to a default set of values.  In it I have 2 arrays.  How do I reset them to the above default value? I.e. nameArray only having Greg in it and no others

Thanks for the help.

Will split points if need be.
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sneeri_c
Asked:
sneeri_c
3 Solutions
 
Mike TomlinsonMiddle School Assistant TeacherCommented:
To make an array grow/shrink you create a new array and copy the values over.

If you want a truly dynamic structure then use an ArrayList instead.
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Ravi SinghSenior Software EngineerCommented:
Hi,

1) The way you have declared the array also implicitly sets the size of the array to 1 with the string "Greg" in index position 0. You can't then add another item in index 1 for example - although you can overwrite "Greg" in index 0 with a new string, e.g:  

nameArray[0] = "New String";

You can also reinitialize the array if needed (although not often done, use dynamic collections if you need to add an unknown amount of items to an array -- see ArrayList below):

nameArray = new string[2]; // reinitializes nameArray to size 2, each position is set to null

The re-initialization loses all the existing values in the old array, if you want to retain those then you need to create another array and move the values from the old array across.

If you are after a dynamic collection then you can use the ArrayList, in such a collection the upperbound is limitless, you can continue adding/removing items as you wish:

ArrayList al = new ArrayList();
al.Add("Greg");
al.Add("Smith");

You can also access the positions using an indexer:

al[0] = "John"; //overwrites "Greg" with "John"

2)

If its the same array with size 0 then just overwrite position 0 with "Greg":

nameArray[0] = "Greg";

If its a different array with a different size, reinitialise the array with "Greg" as the only item in the array:

nameArray = new string[] {"Greg"};
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DarrenDCommented:
In .NET 1.1 you have to do as said above.

In .NET 2.0 you use the Resize property of the array which does the above for you.

Darren

Here is an article on resizing

http://www.informit.com/guides/content.asp?g=dotnet&seqNum=129&rl=1

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