Processing: Creative Coding and Computational Art

PROCESSING: CREATIVE CODING AND COMPUTATIONAL ART
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With regard to the last two operators (== and !=), the double-equal sign (==) tests for
equality, and the symbols != test for inequality; therefore, in the following (non-code)
lines:
if(3==3) would be true.
if(3!=3) would be false.
if(3!=5) would be true.
Conditional operators
The relational operators are often used in conjunction with two conditional operators for
creating somewhat more complex conditions to evaluate. The two operators are
&& (logical and)
|| (logical or)
One minor warning: The operator terms relational and conditional (and also logical) are
used inconsistently, especially around the Web. I’m classifying the operators as specified
on Sun’s site. See http://java.sun.com/docs/books/tutorial/java/nutsandbolts/
opsummary.html for more info.
Following are some examples. To check if x is greater than 3 and less than 10:
if (x > 3 && x < 10) {
//code in here would only
//execute when condition is true
}
To check if x is less than 20 or greater than 50:
if (x < 20 || x > 50) {
//code in here would only execute
//when condition is true
}
To check if the boolean variable myLecturesAreBoring is not true:
if (!myLecturesAreBoring) {
//code in here would only execute when
//condition is true-which is always!!
}
By putting the exclamation symbol in front of myLecturesAreBoring, you are actually
checking for the value to be false.
The relational and conditional operators are used to control the logical flow of your program.
In addition to using the keyword if, you can combine it with the keyword else.
These types of statements, which control the branching logic in your programs, are called
conditional statements. I’ll discuss them in more detail a bit later in this chapter.