What is the difference between initializing a variable inside/outside setup() ?

JoaoBM

Hey!

Is there a difference between initializing a variable inside / outside setup?

Such as this:

int x;

setup() {
x = 5;
}

and this:

int x = 5;

setup() {
}

Thanks in advance!

GoToLoop

• When we run a sketch, all of its ".pde" files are concatenated as 1 valid ".java" file.
• And then it is compiled and run.
• The whole sketch is wrapped up as 1 Java subclass which extends Processing's PApplet class.
• All "global" variables become fields of that subclass.
• And likewise, all functions become methods of that subclass.
• Initializing fields at the same time they're declared happens even before a class' constructor is run.
• Method setup() is called back much later.
• It is safer to initialize fields within setup() b/c there are some PApplet fields, like width and sketchPath, which aren't initialized yet at field declaration time.
• However, if our fields don't depend on those few PApplet "delayed" fields, we can initialize them before setup().