Showing Revision 5 created 05/24/2016 by Udacity Robot.

1. Title:
   2-D Arrays Part 3 - Intro to Java Programming
2. Description:

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   To visit all elements in a Two-D array, you want to loop over the rows and
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   columns. Let's first loop over the rows. So we have a row index i that assumes
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   to values zero, one, and two in this example. Similarly, we'll have a column
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   index j, then in this example, we'll go from zero to one. If we had more
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   columns, of course it would go further. When you have a row of column index,
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   then we can access the element at the i-th row, and the j-th column. So what
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   you see over here. As the general expression for an element at an arbitrary row
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    and arbitrary column. In this case, we just print it and we use printf. So that
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    the print out lines up nicely. So we would now print this element and print
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    that element, that would finish the innerloop. Then the outer loop would pick
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    the next row, we print these two, and then the outer loop picks the last row.
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    And we print those two. Now, of course, we want the numbers to line up nicely,
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    so after printing each row, we want to print a new line. Notice that this
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    statement is contained in the outer loop, because it happens once per row. But
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    its not in the inner loop because we don't want a new line after every of the
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    element. Now, lets look at the missing balance here. Of course, in this simple
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    example I could just say I should be less than three, J should be less than
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    two, but in general, someone might just hand you a two-dimensional array and
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    you should ask it how big it is. Just like with a one-dimensional array, you
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    just use the length field to find out how big an array is. You can get the
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    number of rows from a two-dimensional array by asking it arrayname.length. And
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    the reason for this is that a two-dimensional array is actually an array of
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    one-dimensional arrays. So prices, which looks like this nice tabular
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    arrangement, really is an array of three arrays, one for each row. And so the
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    number of rows is given by that length. Now, we need to look at how many
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    columns we have. Here you have a row. And the length of that row is the number
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    of columns. So in general, you should remember that, for any two-dimensional
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    array, you get the number of rows with this expression, the number of columns
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    with that expression. Now, let's move on to doing something more interesting
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    with two-dimensional arrays and gas prices.