Processing

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Name

extends

Description

Allows a new class to inherit the methods and data fields (variables and constants) from an existing class. In code, state the name of the new class, followed by the keyword extends and the name of the base class. The concept of inheritance is one of the fundamental principles of object oriented programming.

Note that in Java, and therefore also Processing, you cannot extend a class more than once. Instead, see implements.

Examples

  • DrawDot dd1 = new DrawDot(50, 80);

void setup() { 
  size(200, 200);
} 
 
void draw() {
  dd1.display();
} 
 
class Dot { 
  int xpos, ypos;
} 

class DrawDot extends Dot {
  DrawDot(int x, int y) {
    xpos = x;
    ypos = y;
  }
  void display() {
    ellipse(xpos, ypos, 200, 200);
  }
}

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