Processing: Creative Coding and Computational Art

default values based on their specific data type). The properties defined at the top of the
class have global scope within the class, just like variables declared at the top of a sketch
in Processing. Variables declared within the head of a constructor or method (parameters),
or within the constructor/method blocks, are local to that respective structure. This all
works the same way as functions work in Processing.
The constructors are simply methods (functions declared within a class) with the same
exact name as the class and no specified return type. These special methods are invoked
automatically when an object of the class is created. You can have multiple constructors
(each with the same name as the class) as long as the number and type of parameters in
the constructor head (also known as the signature) is different. This also works the same
way as functions work in Processing. Here’s an example of multiple constructors for a
Shape class. Notice that each constructor has the same name as the class, but a unique
parameter list. (This code is not intended to be run.)
class Shape{
// 1st constructor
Shape(){
}
// 2nd constructor
Shape(float x, float y){
}
// 3rd constructor
Shape(float x, float y, float w, float h){
}
}
As I mentioned previously, methods are just functions declared within a class. Like functions,
they can return a value or not, and they can also accept arguments passed into
them. If a method doesn’t return a value, you declare the method using the void keyword.
If the method returns a value, you need to declare it with the specific data type it returns.
Now you’re ready to look at a complete class. Please note that the class definition is just
one part of the process of using a class. Following my description of the BurritoRecipe
class, I’ll show you how to actually incorporate it into a sketch. The class code is a little
lengthy, but I’ll spend some time going over it.
class BurritoRecipe {
// properties
int size;
String tortillaFlavor;
String meatType;
String beanType;
String[]toppings;
int salsaTemperature;
//3 constructors--default, basic, monster
//default burrito recipe constructor
BurritoRecipe (){
}
OBJECT-ORIENTED PROGRAMMING
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