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When we write a program, 
we're figuring out a way to turn

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the brilliant ideas in our head 
into actual code.

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Here I want to talk about a technique 
that many programmers use to do that,

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and it's what we call "pseudocode."

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Now, "pseudocode" is probably a word
you never heard before,

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but basically it's code 
that looks a lot like English

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or really whatever language 
you like to talk in.

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Well, okay, that may not make sense, 
so let's talk through an actual example.

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So let's say that I want to draw 
a nice symmetrical face.

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So I might start by looking at myself 
in the mirror and maybe sketching it out

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and seeing, okay, well I have this oval face.


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I have two eyes, 
and they're about at this level.

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And this is what 
the center of the face is

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and now I have an idea for what
I want my face to look like.

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So I'll start writing it in pseudocode.

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So let's see, the first thing 
we'd want to do is draw the face,

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which is an oval, in the center.

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Then we'd want to draw the two eyes,
which are two ovals,

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about two thirds up the face, 
and one fifth the size of the face.

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Not exact math there 
just looking at my own face.

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And then we draw the mouth, which is 
a line going halfway across the face,

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and maybe one third of the way up.

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So notice how I write 
my pseudocode as comments

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by starting each line
with the two slashes here.

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That way I can write my pseudocode
in the program itself

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and not have to worry about 
getting any syntax errors

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because the program will ignore comments.

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Now that I've written this in pseudocode, 
I can spend the time to turn

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each of these lines of pseudocode 
into actual bits of code

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Right? So let's see, for the face 
I need an oval in the center.

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For that I'll use the ellipse function for,
and I'll, you know, figure out

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the center of the screen here,
and figure out an eye size.

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Okay?
That looks good.

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For the eyes once again 
those are ellipses.

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Everything on my face is an ellipse. 
I'm very round.

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And it's going to be, let's see, 
we'll do some math here to get the eyes

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at a nice place, and make them
about a fifth the size.

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Okay, that looks good for the first eye.

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I'll just copy paste, make the next eye.

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Great!

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Now I can even leave my pseudocode 
for a friend to implement,

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and they probably could, 
because they can, you know,

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I have given this really nice description.

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So I'm going to do that here, 
because, you know, we're friends, right?

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So, you might think this is silly.

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Why are we going through the effort
to write our program twice?

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First in human language 
and then in program language.

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Well, this example was pretty simple, 
but pretty soon you'll be building

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more complex programs, 
and it may be hard for you to keep

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the whole program in your head 
before coding it.

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So what I usually do is write the general
idea in pseudocode first,

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and then I'll spend more time on
the details of each part of that idea,

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converting each line 
of pseudocode into real code.

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I think you'll find that once you start
using pseudocode

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you'll do it more and more.

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Try it in your next program and see.