Lab 18 - 2D Arrays

This Tuesday lab will focus upon 2D Arrays, which is just arrays contained within arrays. These arrays become significantly more complex as we continue to nest them, which we can do, such as making an array that contains arrays which contain arays and so on. To focus upon 2D Arrays, students will be placing the final touches on a Connect4 application.

For ease of access, here is the javadoc.

Pre-Step:

With nearly all Tuesday labs, you will want to compile and ensure that it works. Once you ensure this, it is a good idea to check out the main function and follow the program execution throughout both available files.

If you are also unfamiliar with the game of Connect4, you can check out the Wikipedia to learn more.

Step 1: Self-Explanation

There are only two self-explanations that must be completed for this lab, these may require some additional problem-solving. I would recommend to illustrate your method execution on a piece of paper to help with your understanding.

2D Arrays can be difficult to visualize so that is why it is being urged to draw them!

Step 2: Implementation

After you finish with your self-explanations you are free to move onto implementing them within your own code, after implemented it may be helpful to draw-along with its execution to help solidify your understanding.

Step 3: Testing

After finishing you implementation it will help to run through the game and try to create a victory case and see if it functions correctly. Optionally, you can also create more test to test all cases possible for victory conditions.

Step 4: Turning In

Once finished, be sure to submit your TwoDArraysUtility.java and show your self-explanations to the TAs. Summer session does not need to show their self-explanations but it is still highly recommended to complete.

Additional Information

2D Arrays

2D Arrays are almost exactly like arrays except that each index in the initial array contains another array which can also be indexed.

//This 2D Array is empty, but we can still index values within it.
int[][] twoByTwo = new int[2][2];
int[] firstRow = int[0];
int[] secondRow = int[1];

We can illustrate 2D Arrays by viewing each nested array as a row.
Using an int[4][4] 2D Array name nums:
[[0, 1, 2, 3],
[4, 5, 6, 7],
[8, 9, 10, 11],
[12, 13, 14, 15]]
If an array was initialized as such we would say nums[0][3] to retrieve the value 3.

If we wanted to print the entirety of this 2D Array, we could use two for-loops:

for(int i = 0; i < nums.length; i++) {
    for(int j = 0; j < nums[i].length; j++) {
        System.out.println(nums[i][j]);
    }
}

If you are still running into troubles there is an entire section within the zyBooks going over 2D Arrays, which may help you.