Processing: Creative Coding and Computational Art

Ternary operator
The last conditional structure I want to show you is Java’s ternary operator—meaning that
it uses three operands. The ternary operator takes some time getting used to, and some
people never get used to it. I tend to hardly ever use it, but other people use it a lot, so it’s
worth learning. It’s logic is similar to an if...else statement. Here’s an example:
//some variables
int karma;
boolean isStillReadingThisBook;
// Here's the if/else version:
if (isStillReadingThisBook){
karma = 100;
else {
karma = 50;
}
// Here's the ternary operator version:
karma = isStillReadingThisBook ? 100 : 50;
The ternary version looks pretty terse and cryptic. Its form is really a throwback to an older
style of programming. However, as you can see, it is efficient. The condition is tested, in
this case the boolean variable isStillReadingThisBook; if the condition is true, then the
first value after the ? is returned and assigned to the karma variable; if it is false, then
the value after the : is returned. It’s really up to you whether you want to use this structure.
You can always use the more verbose if...else to accomplish the same thing.
Arrays and loops
The next section looks at arrays and loops. I’ve grouped these somewhat large topics
together because of their interconnectedness. Arrays and loops aren’t that complicated as
concepts, but they can get a little hairy for newbie coders to implement. I’ll be using them
to expand on two previous sketches: the stepped radial gradient and the bouncing ball.
These examples will illustrate the power of arrays and loops and also begin to show you
the potential of code as a creative medium.
Arrays
There are times in coding when you’ll want to assign many values to a single variable. For
example, maybe you have 100 balls and you want to keep track of each of their x positions.
The problem with using a primitive variable is that it can only hold one value at a
time. Thus, you would need 100 separate variables to account for each ball’s x position.
Arrays were developed to solve this problem; they are single data structures that hold
multiple values. If I wanted to animate all 100 balls, there are very easy ways to change the
100 x positions stored within the array. You can think of an array as a desk with multiple
drawers. On the one hand, an array is a single entity, referred to by a single name; on the
other hand, the array can hold many separate values, each accessible through an indexing
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