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Alright so why are we getting these
errors that showed up at the end of the

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last video? Well we've got errors because
you must have valid code inside each of

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the code blocks. A comment doesn't count.
Notice that there's a red tick in the

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right margin next to lines 15 and 18, and
I can select them up here, and also there's this

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red squiggle under each comment on
line 15 and 18. Now this can be confusing

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when you're starting but it's the syntax
rules of Python.

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You must have code inside a code block.
If there's no code, and that includes

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just having a comment, then you'll get an
error like this. So notice that there

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isn't an error on line 21 or line 24.
There is code inside those two blocks,

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so we don't get that error. If getting an
error wasn't confusing enough though, the

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error message makes it even worse. And if I
hover over one of them again, you can see the

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error we're getting there is: indent
expected. But of course, looking at that

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you can see those comments are already
indented - they're obviously indented.

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So we can see that on the screen. You may
not see an error if you're using a

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different IDE, but you will get it when
you try to run your code. So things like

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this can have you tearing your hair out.
Fortunately, there are very few times

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when something like this happens, and now
that I've pointed it out, you'll remember

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it and avoid tearing your hair out.
What you'll often find programmers doing,

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is adding a dummy bit of code inside the
indented block, to clear this error.

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So there's a specific keyword in Python for that
and that's called pass. So I'm going to

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come up here to line 16, tab over and
type pass. So come down to line 19,

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tab over and type pass again. Now pass
doesn't do anything, but it makes the

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code syntactically correct. So think of
it as a placeholder for the real code

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that you'll add later, and you can see
that that's fixed the errors and we've

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now got the basic structure of our code.
Alright so it's time to work out what

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we really want to do in place of those
pass statements. If the computer had to

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guess higher, well then we alter the
low value of the range and go around the

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loop again. So let's do that. So I'm going
to replace that pass on line 16 with low

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equals guess plus 1,  which is in
line with the comment that I've

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added on line 15. Now similarly, if we have
to guess lower, then the new high value is

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one less than the current guess. So
come out to line 19, replace the pass,

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and it's going to be high equals guess
minus 1. Alright so the last step now

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in our algorithm, is to break out of the
loop when the guess is correct. So we're

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going to come down here. Then on line 22,
we're going to add the keyword break

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so that we do just that. We break out
of the while loop if the computer has

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successfully guessed it. If you've
programmed in other languages, you might

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be wondering if we could use a case or
switch there. Don't bother searching for

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how to do that in Python. Python doesn't
have a case or switch statement. If you

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haven't programmed before, that won't mean
much to you, don't worry about it.

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They don't exist in Python. Alright, so
that's our algorithm implemented with

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Python code. So we're doing a bit more.
We're also counting the number of

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guesses. So that means therefore we
should increase the count before the

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loop goes around again. So we need to
come down and add that code, and we

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both need to add it at the same
 level as the if, and I'm gonna

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put it down here on line 27. Actually, what
I'll do is I'll come down here and I'll

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just, to be consistent with our code,
we're going to take that up one line,

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and over here, on line 26 now, I'm going to
type guess, or guesses rather, equals

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guesses plus 1. So be careful with the
indentation there. That line must be

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indented one level, as I have it there, so
that it's inside the while loop but not

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inside the else block. So for now, we're going
to ignore this suggestion from IntelliJ.

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I'm going to talk about that in the next
video, but at this point we've now

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finished, our program is finished. Check
your code carefully and then in the next

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video, we'll test it out to make sure it
works. See you in the next video.