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Java programmers have a wide array of tools at their disposal. Among these, are arrays (sorry). An array allows you to store multiple related variables of the same type.
- What are arrays
- Declaring Arrays
- Using Arrays
- Multi-Dimensional Arrays
Arrays allow you to store a list. For example, let's say you want to store the age's of several people. You can create an array.
Declaring an array is easy enough; you just add double brackets () to then end of the data type. Here is an example.
Next, you must fill your new variable. This calls for another example:
Numbers = new double;
Ages = new int;
Stuff = new float;
StateSizes = new float;
The numbers inside the brackets are the "dimensions" of the array. The dimensions are the number of elements in the array.
Now you have a freshly declared array. So, how do you use it? Well, you can set any element of the array using brackets. Observe:
Numbers = 104.493;
Ages = 14;
Stuff = 43.49
StateSizes = Stuff / 2; //This is Hawaii
Simple enough. You can assign values to as many elements in a list as you want.
I am sure a few of you have thought to yourselves, "You dolt, Hawaii is the fiftieth state, not the forty-nimth." Well maybe not in those words. First of all, I am not a dolt (just thought I would clear that up). Second of all, I am glad you noticed. The first element in Java is zero. That means the last element in an array with fifty elements is forty-nine. An array with fifty element does not have an element numbered fifty. You should always remember this. It is a common mistake for Java programmers.
In Java, you can make arrays of arrays. These are similar to multi-dimensional arrays, but not exactly the same. The difference is trivial however. Here is an example of a multi-dimensional array.
int BoardSize = new int;
These arrays act pretty much like one-dimensional arrays.
Our next chapter will introduce you to the "if statement" - just another one of a vast array of tools available to Java programmers.
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