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

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the brilliant ideas in our head [br]into actual code.

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Here I want to talk about a technique [br]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[br]you never heard before,

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

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or really whatever language [br]you like to talk in.

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

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

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

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and seeing, okay, well I have this oval face.[br]

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

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And this is what [br]the center of the face is

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and now I have an idea for what[br]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 [br]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,[br]which are two ovals,

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

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Not exact math there [br]just looking at my own face.

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And then we draw the mouth, which is [br]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 [br]my pseudocode as comments

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by starting each line[br]with the two slashes here.

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That way I can write my pseudocode[br]in the program itself

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and not have to worry about [br]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, [br]I can spend the time to turn

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each of these lines of pseudocode [br]into actual bits of code

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

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

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

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Okay?[br]That looks good.

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For the eyes once again [br]those are ellipses.

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

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

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at a nice place, and make them[br]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 [br]for a friend to implement,

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and they probably could, [br]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, [br]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[br]to write our program twice?

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First in human language [br]and then in program language.

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

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

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the whole program in your head [br]before coding it.

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

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

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converting each line [br]of pseudocode into real code.

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I think you'll find that once you start[br]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.