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Arrays


Introduction:
Welcome, this page will teach you about Arrays within Java.

What is an Array?
An array is a variable which holds more than one value, in effect, it's a list of values attached to a variable name.

When are Arrays Used?
Arrays are very useful for holding lists of values for certain scripts. For example; holding the id of each button that has been activated within a game. Once a button is clicked, it's ID gets added to the array of clicked buttons which then gives a list of clicked button ids to be used at a later date.

Examples:
First we need to decide what type of variable the array will hold, the amount of data it will hold (maximum) and we also need a variable name. Once we have those we can create our new array using the format {type}[] {variable name} = new {type}[{size}]:

  1. int[] myArray = new int[10];

The above code will create a new variable named "myArray" which is equal to a new int array of 10 values (technically it is 9 values, and 0). Now we are able to insert values in to the 10 spaces within our new array, such as...

  1. myArray[0] = 0;
  2. myArray[1] = 10;
  3. myArray[2] = 100;
  4. myArray[3] = 1000;
  5. myArray[4] = 10000;

Next lets output the values of each placement in our array...

  1. for (int i=0;i<myArray.length;i++){
  2. System.out.println(myArray[i]);
  3. }

You are also able to edit previously set values. Lets change the first value (0) to 100000 then re-output all the values to our console and observe the change...

  1. myArray[0] = 100000;
  2. for (int i=0;i<myArray.length;i++){
  3. System.out.println(myArray[i]);
  4. }

Here is the output to the console we get in total once we run the program. As you can see;
1 - There is a change in value 0, as we attempted.
2 - There are alot of "0"s after the ending 4 (5) value of our integer array which we had set. This is because, even if the placements don't have a custom, user set value, they still exist and have a default value.

0
10
100
1000
10000
0
0
0
0
0
100000
10
100
1000
10000
0
0
0
0
0

Finished!

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