What is the coolest thing you can do in <10 lines of simple code? Help me inspire beginners! [closed]

language-agnostic

I'm looking for the coolest thing you can do in a few lines of simple code. I'm sure you can write a Mandelbrot set in Haskell in 15 lines but it's difficult to follow.

My goal is to inspire students that programming is cool.

We know that programming is cool because you can create anything you imagine - it's the ultimate creative outlet. I want to inspire these beginners and get them over as many early-learning humps as I can.

Now, my reasons are selfish. I'm teaching an Intro to Computing course to a group of 60 half-engineering, half business majors; all freshmen. They are the students who came from underprivileged High schools. From my past experience, the group is generally split as follows: a few rock-stars, some who try very hard and kind of get it, the few who try very hard and barely get it, and the few who don't care. I want to reach as many of these groups as effectively as I can. Here's an example of how I'd use a computer program to teach:

Here's an example of what I'm looking for: a 1-line VBS script to get your computer to talk to you:
CreateObject("sapi.spvoice").Speak InputBox("Enter your text","Talk it")
I could use this to demonstrate order of operations. I'd show the code, let them play with it, then explain that There's a lot going on in that line, but the computer can make sense of it, because it knows the rules. Then I'd show them something like this:
4(5*5) / 10 + 9(.25 + .75)
And you can see that first I need to do is (5*5). Then I can multiply for 4. And now I've created the Object. Dividing by 10 is the same as calling Speak - I can't Speak before I have an object, and I can't divide before I have 100. Then on the other side I first create an InputBox with some instructions for how to display it. When I hit enter on the input box it evaluates or "returns" whatever I entered. (Hint: 'oooooo' makes a funny sound) So when I say Speak, the right side is what to Speak. And I get that from the InputBox.

So when you do several things on a line, like:
x = 14 + y;
You need to be aware of the order of things. First we add 14 and y. Then we put the result (what it evaluates to, or returns) into x.

That's my goal, to have a bunch of these cool examples to demonstrate and teach the class while they have fun. I tried this example on my roommate and while I may not use this as the first lesson, she liked it and learned something.

Some cool mathematica programs that make beautiful graphs or shapes that are easy to understand would be good ideas and I'm going to look into those. Here are some complicated actionscript examples but that's a bit too advanced and I can't teach flash. What other ideas do you have?

Solution 1:

Enter this code in your address bar (in your browser) and press enter. Then you can edit all the content of the webpage!

javascript:document.body.contentEditable='true'; document.designMode='on'; void 0

That is the coolest "one-liner" I know =)

Solution 2:

When I first wrote this.

10 PRINT "What is your name?"
20 INPUT A$
30 PRINT "Hello " A$
40 GOTO 30

It blew people away! The computer remembered their name!

EDIT: Just to add to this. If you can convince a new programmer this is the coolest thing they can do, they will become the good programmers. These days, you can do almost anything you want with one line of code to run a library somebody else wrote. I personally get absolutely no satisfaction from doing that and see little benefit in teaching it.

Solution 3:

PHP - the Sierpinski gasket a.k.a the Triforce

OK, it's 15 lines of code but the result is awesome! That's the kind of stuff that made me freak out when I was a child. This is from the PHP manual:

$x = 200;
$y = 200;

$gd = imagecreatetruecolor($x, $y);
 
$corners[0] = array('x' => 100, 'y' =>  10);
$corners[1] = array('x' =>   0, 'y' => 190);
$corners[2] = array('x' => 200, 'y' => 190);

$red = imagecolorallocate($gd, 255, 0, 0); 

for ($i = 0; $i < 100000; $i++) {
  imagesetpixel($gd, round($x),round($y), $red);
  $a = rand(0, 2);
  $x = ($x + $corners[$a]['x']) / 2;
  $y = ($y + $corners[$a]['y']) / 2;
}
 
header('Content-Type: image/png');
imagepng($gd);

sierpinski gasket