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<h3>Inheritance</h3>

<p>A class can be defined using another class as a foundation. In object-oriented

programming terminology, one class can inherit fi elds and methods from another.

An object that inherits from another is called a subclass, and the object it

inherits from is called a superclass. A subclass extends the superclass.</p>

<p><a href="http://processing.org/learning/basics/inheritance.html">Original Processing.org Example: Inheritance</a><br>

<div class="learning-demo"><script type="application/processing">

SpinSpots spots;

SpinArm arm;

void setup()

size(200, 200);

smooth();

arm = new SpinArm(width/2, height/2, 0.01);

spots = new SpinSpots(width/2, height/2, -0.02, 33.0);

void draw()

background(204);

arm.update();

arm.display();

spots.update();

spots.display();

class Spin

float x, y, speed;

float angle = 0.0;

Spin(float xpos, float ypos, float s) {

x = xpos;

y = ypos;

speed = s;

}

void update() {

angle += speed;

}

class SpinArm extends Spin

SpinArm(float x, float y, float s) {

super(x, y, s);

}

void display() {

strokeWeight(1);

stroke(0);

pushMatrix();

translate(x, y);

angle += speed;

rotate(angle);

line(0, 0, 66, 0);

popMatrix();

}

class SpinSpots extends Spin

float dim;

SpinSpots(float x, float y, float s, float d) {

super(x, y, s);

dim = d;

}

void display() {

noStroke();

pushMatrix();

translate(x, y);

angle += speed;

rotate(angle);

ellipse(-dim/2, 0, dim, dim);

ellipse(dim/2, 0, dim, dim);

popMatrix();

}

</script><canvas width="200" height="200"></canvas></div></p>

<div style="height:0px;width:0px;overflow:hidden;"></div>

<div class="code"><pre name="code" class="processing">// All Examples Written by Casey Reas</a> and Ben Fry</a>

// unless otherwise stated.

SpinSpots spots;

SpinArm arm;

void setup()

{

size(200, 200);

smooth();

arm = new SpinArm(width/2, height/2, 0.01);

spots = new SpinSpots(width/2, height/2, -0.02, 33.0);

}

void draw()

{

background(204);

arm.update();

arm.display();

spots.update();

spots.display();

}

class Spin

{

float x, y, speed;

float angle = 0.0;

Spin(float xpos, float ypos, float s) {

x = xpos;

y = ypos;

speed = s;

}

void update() {

angle += speed;

}

}

class SpinArm extends Spin

{

SpinArm(float x, float y, float s) {

super(x, y, s);

}

void display() {

strokeWeight(1);

stroke(0);

pushMatrix();

translate(x, y);

angle += speed;

rotate(angle);

line(0, 0, 66, 0);

popMatrix();

}

}

class SpinSpots extends Spin

{

float dim;

SpinSpots(float x, float y, float s, float d) {

super(x, y, s);

dim = d;

}

void display() {

noStroke();

pushMatrix();

translate(x, y);

angle += speed;

rotate(angle);

ellipse(-dim/2, 0, dim, dim);

ellipse(dim/2, 0, dim, dim);

popMatrix();

}

}</pre></div>