1. What is iteration? I mean, what is iteration? Seriously, what is iteration?

2.  Iteration is the process of repeating a set of rules or steps over and over again

3.  Loops gives you the ability to repeat a set of code over and over again.  Loops will execute until a condition is met …  If the condition is never met, you have what’s called an endless loop … and that is not good!!  There are three different types of loops  WHILE loop  DO-WHILE loop (really, there is a difference!)  FOR loop

4.  The while loop executes the code inside it’s brackets until a condition is met. while (condition) { // if condition is true … do this do that do whatever you want! } //end while loop  So why are they useful? Consider a repetitious situation on the following slide …

5. size(200,200); background(255); // Legs stroke(0); int y = 80; // Vertical location of each line int x = 50; // Initial horizontal location for first line int spacing = 10; // How far apart is each line int len = 20; // Length of each line // Draw the first leg. line(x,y,x,y + len); // Add spacing so the next leg appears 10 pixels to the right. x = x + spacing; // Continue this process for each leg, repeating it over and over. line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); x = x + spacing; line(x,y,x,y + len); There must be an easier way!!

6. size(200,200); background(255); int y = 80; // Vertical location of each line int x = 50; //Initial horizontal location for first line int spacing = 10; // How far apart is each line int len = 20; // Length of each line // A variable to mark where the legs end. int endLegs = 150; stroke(0); // Draw each leg inside a while loop. while (x <= endLegs) { line (x,y,x,y + len); x = x + spacing; } Yes, there is an easier way! Same outcome far fewer lines of code!

7.  Exit conditions are extremely important!  I don’t want any endless loops … consider the following int x = 0; while (x < 10) { println(x); x = x – 1; } // when will this loop stop? DON’T DO THIS!!

8. 1.Create a program that draws a series of ellipses, each one smaller than the previous. Your end result should look like a target. Extra: create a random number for the colour of the ellipses. See example … trippy man!

9.  The do-while loop is the same as a while loop, but the test comes after the loop, instead of before.  The following is an example … x=0; while (x<10) { x = x + 1; ellipse(x,y,10,10); } //will run 10 times OR x=0; do { x = x + 1; ellipse(x,y,10,10); } while (x<10) //will run 11 times

10. 1.Add several balls to yesterday’s program. 2.Add a user controlled ball to the screen that tries to cross the screen, a la frogger.

11.  Much like While loops, FOR loops are a block of code that repeats.  The difference is that a FOR loop executes a given number of time. Example: void setup () { size(500,500); frameRate(4); } void draw() { fill(0); for (int x=100; x > 0; x=x-5){ fill(random(0,255),random(0,255),random(0,255)); ellipse(100,100,x,x); }  Practice: combine this with your maze. Make your character flash colour like in this example.  Practice: make Zoog’s eyes change colour hypnotic style