1. From last time…
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Quiz 2: Variables, Conditionals, & Loops!
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We started to organize our sketches by defining
functions and simplifying our draw loop!
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I sent out / posted expectations for Iteration 1!
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I’ve cancelled class next Monday, 10 Feb 2014

2. Iteration 1
CAP

3. Expectations
We will have 5 groups:!
! 1 GenArt, 1 DataViz, and 3 Game groups!
•
•
Mon, 17 Feb: you will show Iteration 1 to your
group and take notes (4–5 minutes per student)!
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Wed, 19 Feb: you will submit your code, the
notes you took in class, and an Iteration 2 plan
before class (probably via Sakai…)

4. Feedback
•
What works? What do you like?!
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What doesn’t work? How could it be improved?!
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Any other thoughts or comments?

5. Ideate
Empathize
Define
Prototype
Test
The Iterative Design Process

6. Functions II
CAP

7. Functions
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Functions allow Modularity and Reusability!
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They allow us to have code which follows the
principle of DRY: “Don’t Repeat Yourself”

8. “Every piece of knowledge must have a
single, unambiguous, authoritative
representation within a system.”
The Pragmatic Programmer!
Hunt & Thomas on the Principle of Don’t Repeat Yourself (DRY)

9. DRY vs. WET
•
Non-DRY coding is often called WET coding:!
! - Write Everything Twice!
! - We Enjoy Typing!!
•
If you are repeating yourself in code, you should
automatically start thinking about functions…

10. Functions
returnType functionName( argumentList )
{
// the function code is here
}
•
Memorize the structure of a function!!
•
You need to be able to “read” functions

11. Random Fill Color
void setRandomRGBFillColor() {
fill(random(255),random(255),random(255);
}
“This function takes no arguments, sets the fill color
to a random RGB color, and returns nothing.”

12. Random Positions
float randomXPosition() {
return random(width);
}
!
float randomYPosition() {
return random(height);
}
“This function takes no arguments, generates a
random value based on width, and returns a float.”

13. Demo!
Square & Circle

14. Arguments
•
When need a function to use a value that we give
to it, we give it arguments!
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size(400,300); has two arguments!
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Arguments are said to be “passed” to the function,
and must follow some rules:!
! - they must have the correct number of arguments!
! - they must have the correct type of arguments

15. Passed by Copy
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When arguments are passed, they are said to be
“passed by copy”!
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This means that your argument is duplicated
(copied) and the copy is handed to the function!
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The function can use/abuse the copy and return
a value, without ever affecting the original value
passed in

16. Demo!
Passing An Argument

17. Quiz 2
CAP

18. For next time…
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Read Shiffman, p. 121–130 (Objects I)!
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Two weeks until Iteration 1 is due