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We can use a phrase, the store many values at the same time.

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I hope you're proud of yourself, because so far you covered most of the fundamentals you need to build

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Java applications, namely you learn how to store and update information using variables, control how

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your code runs using effluents, which organize your code into functions and running your code many

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times using far loops and while loops, the last thing you need to learn about is arrays.

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So in this lesson, you're going to use arrays to store many values at the same time.

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First thing you need to do is create a new job, a project named Section six, and inside the project

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create a new file named intro to Erase Java and as always, make sure the class has a main method.

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We can store values into an array, an array lets you store many values at a time.

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Arrays in Java look like this, if I want to store many integers at once, then I can put square brackets

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next to the integer type and now I can store many integer values in one variable.

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That being said, an array can hold many values, but all of them have to share the same type.

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For example, integers, stars, an array of integer values, words that stores an array of string values.

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Decimals stores an array of double values and letters, stores, an array of characters.

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And so from a visual standpoint, this is how a variable stars an array.

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Looking at all these arrays, you might be thinking, what is the dot, where did that come from?

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Good question.

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I'm glad you asked.

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The DOT is a reference.

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A variable cannot store the array directly at stores, a unique reference, and it's the reference that

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points to the array.

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This is a really important distinction to make.

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I'm going to include these bullet points in your cheat sheet, because I think this is something that's

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really important to be aware of, especially as we go through the remaining code.

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So instead of your class, you're going to find an array that stores, kingdoms, I'm going to put an

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array that can hold many strings.

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The variable is going to be called kingdoms and it's going to store for string values.

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Northumbria and East Anglia.

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Yay for short.

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Now, try printing the array.

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And what is this seven to six debate, what does this spring represent?

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It's kind of weird.

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Well, not really.

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Think about it.

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Pretty line Prince.

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Whatever is inside the verbal kingdoms and what's inside the verbal is a unique reference represented

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by a white dot.

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So instead of actually printing the array value itself, what we're printing is the reference that points

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to it.

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So how do we access values from an array, how do we access an array elements, you can access an element

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by referring to its index number.

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By the way, an element is just a value inside of an array in the coding world.

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We say elements.

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And every element has an index, an index is a number that represents a position.

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It starts at zero and counts up the number of elements.

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So Jane would have an index of zero.

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Joe would have an index of one.

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And Joe would have an index of two.

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If you want to access an element, just type Geary's name, followed by square brackets and inside the

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brackets, write the index of the element that you want to access.

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So index is zero would point to the first element in the array.

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Jane, index one Joe and index to Joe.

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And so back in our code, we can print each Kingdome individually, I'm going to print the kingdom at

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Index zero Mersea.

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The kingdom at index won.

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The kingdom at index two and the one in the next three, I can now run the code.

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And as you can see it, access to each element by referring to its index number and then it printed

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it.

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I prepared this visual for you just so that you can see what's going on.

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OK, now, more often than not, you're going to specify an index that's out of range and Jeb is going

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to yell at you and crush, you cannot refer to an index number that doesn't exist.

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You cannot refer to an index beyond the bounds of the array if you try to.

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Jeb is going to throw an error and it's going to crash.

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And so the kingdom, right, it had four elements, but because we start counting at zero, the last

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element is going to have an index that's exactly one less the length of the array three.

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So in your code, if we try to access an element that index for let's do just that.

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Run the code.

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And Java crashes, the last print statement throws an error because the next four is out of bounds.

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You cannot access an element from an index that doesn't exist.

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So I'm going to delete the last print statement and clear the output.

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In this video, you use the arrays to store many values in the same variable and then you accept each

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element using its index, you define a string array that stores kingdoms, each element has an index

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and you access each kingdom by referring to the index number.

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From a code perspective, the runtime appears as follows.

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I also showed you that we can't refer to an index number that doesn't exist, the kingdom's variable

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had four elements, and because we start counting from zero, the index ranges from zero to three.

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So if you try to access an element, that index for Jeb is going to throw an error and your code is

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going to crash.