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>> ROB BOWDEN: Hi, I'm Rob, and let's jump
into the hacker edition of Mario.

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So first thing we need to do is
get the height from the user.

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Here we're asking them for a
non-negative integer less than 24 and

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we're using the CS50 GetInt function
to grab that integer from the user.

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We see we're inside of a do-while loop
that will continue looping as long as

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height is greater than
23 or less than 0.

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And so we'll continue until the user
actually gives us what we want.

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>> Once we have that height, we get to
the main for loop of our program.

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So let's first look at an example
from the pset spec.

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We see in this example that when we
enter a height of 4, the bottom row

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first prints four hashes, two spaces,
and four more hashes.

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>> Then one row above that prints one
space three hashes, two spaces to

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separate the pyramids, and
then three more hashes.

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And above that, two spaces, two hashes,
two spaces, two hashes.

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And finally, three spaces one
hash, two spaces one hash.

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So you should start to notice
the pattern here.

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>> Let's look at the code for how
we're going to do that.

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We see here that we're iterating
over all rows of the pyramid.

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First we want to calculate
the number of spaces.

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And remember that we have to start at
the top of the pyramid and work our

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way down since we can't print the
bottom then one row up and

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then one row up.

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So at the top of the pyramid, notice
that the number of spaces is equal to

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height minus 1.

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We're going to print three spaces then
one hash and then two spaces to

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separate and another hash.

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>> So spaces is equal to
height minus row.

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If the row is 1 and our height is 4,
that'll give us 3 spaces, as we want.

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Then this for loop just prints
that number of spaces.

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If spaces is three, then we're going to
create a single space three times.

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>> Continuing, now we want to print the
hashes of the left pyramid, which is

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just equal to the row number.

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Looking back here, in row
one, we print one hash.

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In row two we print two, in
row three we print three.

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So we simply loop row times
printing hash symbol.

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Then for all rows of the pyramid, we
print exactly two spaces to separate

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those pyramids.

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>> And finally, we want to print the right
side of the pyramid, which is

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again the same number of hashes
as the left side.

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And so it's the same exact
for loop as above here.

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Finally, we need to create a new line in
order to move on to the next row of

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the pyramid and continue printing.

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And that's it.

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My name is Rob and this was Mario.

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