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Before we start, did you try solving the workbook yourself?

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If not, please click the link in the resources folder and follow the instructions for this workbook.

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Welcome to Workbook 6.14, the last workbook of this section.

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The first thing I'm going to do is copy this function into our class, because what it will do is return

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a random number between zero and 99.

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Now we get to write a function that prints the contents of an array.

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So the function is called print to the array public static.

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It's going to be void and it will expect a2d array that can store int elements called.

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Well, I guess just a ray.

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So the function uses a nested loop.

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The inner loop prints each row in one line.

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So four and I is equal to zero.

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The outer loop is going to keep running so long as I is smaller than the number of rows inside of the

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studio array plus plus array length for a two RD array represents the number of rows that this array

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has, and each run of the outer loop is going to run the inner loop to completion.

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So here we can say int j is equal to zero.

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J is smaller then however many elements there are in row I so row I length.

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J plus plus, and the inner loop runs for as many elements as there are in Row II, which means we can

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use this print statement to index every single element J in Row II and print it all right.

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After the inner loop runs to completion, print a new line.

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Very simple.

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All right.

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And now we call print to dx array for the following array.

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Just to test it out.

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So here.

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Bridge going to say print to the array array.

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I'm not just going to run it.

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I will visualize the runtime.

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So we'll step inside, print to the array.

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The array parameter, as you can see, has three rows and ten elements per row.

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Which means every run of the outer loop is going to run the inner loop ten times.

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So here we start at I equaling zero, which corresponds to row zero.

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The inner loop will keep running so long as J is smaller than the number of elements inside of row zero.

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So this inner loop is going to run ten times the first time it runs.

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IE is zero.

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J is zero, printing 48 I is zero, J is one printing 56, I is zero.

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J is two once again also printing 56.

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i0j is three this time printing 76 and the inner loop is going to keep running for every single element

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inside of row zero.

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After the inner loop runs to completion, it prints every single element in row zero.

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And now we're ready to print a new line.

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All right, Now, the outer loop runs a second time.

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This time I equals one representing row one.

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And once again, every run of the outer loop is going to run the inner loop to completion.

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It's going to run so long as J is smaller than the number of elements inside of row one.

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So the inner loop will run ten times.

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Here we index element zero of row one.

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Here we index element to one over oh one.

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Here we index element two from row 173.

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All right.

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And this is just going to run seven more times.

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When J equals nine will be the last time that this inner loop runs.

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So the inner loop runs to completion, and then we print a new line so that we prepare for the next

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run of our outer loop.

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Now I equals two representing row two, and then we use the inner loop to print every single element

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in row two.

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And once the inner loop runs to completion, we print a new line and we are done.

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Now.

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A-plus plus increases.

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AI to three.

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Three is not smaller than the number of rows three.

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So our outer loop breaks we are done.

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Print two DX array is effectively capable of printing any two dx array that we pass in.

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This is just beautiful.

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So now we can move on.

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Delete the array if you achieve the result.

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Indeed we did.

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Now create a 2D array with 100 rows and ten columns.

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By columns I mean ten elements per row.

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So we'll just set this equal to a new 2D array that stores ten rows.

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Or was it 100 rows?

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And ten columns, ten elements per row.

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We'll just say Java Sea, random numbers dot Java, Java, random numbers.

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It just prints 100 rows and ten elements per row.

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Ten columns.

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OC use a nested loop to populate the array with random numbers before calling print to the array.

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All right, so what we'll do?

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This will create a loop.

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The outer loop starts and equaling zero.

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The outer loop is going to keep running so long as I is smaller than the number of rows is smaller than

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array length, which means the outer loop is going to run 100 times.

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And every time the outer loop runs, we need to run the inner loop so that we can go through every single

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element in that row.

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So the inner loop will keep running so long as J is smaller than the current row where iterating through

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is length.

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J plus plus.

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And so now here we can basically index every single row, every single element in each row, and set

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that equal to a random number.

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All right.

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I'm only going to visualize execution for the first two rows, and then I will let the runtime continue

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naturally.

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All right.

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So here we have an array with 100 rows and ten elements per row.

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Obviously, we're not going to break point through all of this.

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So first I equals zero corresponding to row zero.

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Every time the outer loop runs, it runs the inner loop for as many elements as there are in the current

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row.

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So Jay starts off at zero.

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Here we update the element at index zero zero to a random number.

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Here we update the element zero one to a random number.

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Here we update the element to zero two to a random number.

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And this keeps on going.

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The inner loop is going to run to completion.

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All right, now I equals one corresponding to row one.

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This inner loop is going to keep running so long as J is less than the number of elements in row one.

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So J starts off at zero, element zero of row one gets updated to a random number, element to one of

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row one.

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And now the inner loop is going to update every single element inside of row one.

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After we update all over oh one.

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Now we move to row two.

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I'm not going to do all of that.

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That will take a long time.

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So let's just press continue.

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Let's remove this.

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Let's remove these breakpoints.

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Then press continue.

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All right.

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Here you can see we've updated every single row, every single element in that row.

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Now it's just time to print it.

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We've already demonstrated that print to the array can print any to the array that we pass in.

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So we'll just step over this.

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And beautiful.

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As you can see.

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We printed a 2D array of random numbers.

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I hope you enjoyed this breakpoint session.