. (dot)

Category: Structure

Complexity: Expert

Description

Provides access to an object’s methods and data. An object is one instance of a class and may contain both methods (object functions) and data (object variables and constants), as specified in the class definition. The dot operator directs the program to the information encapsulated within an object.

Related

Example

Code:
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// Declare and construct two objects (h1 and h2) of the class HLine
HLine h1 = new HLine(20, 1.0);
HLine h2 = new HLine(50, 5.0);

void setup() {
  size(200, 200);
}

void draw() {
  if (h2.speed > 1.0) {  // Dot syntax can be used to get a value
    h2.speed -= 0.01;    // or set a value.
  }
  h1.update();  // Calls the h1 object's update() function
  h2.update();  // Calls the h2 object's update() function
}

class HLine {  // Class definition
  float ypos, speed;  // Data
  HLine (float y, float s) {  // Object constructor
    ypos = y;
    speed = s;
  }
  void update() {  // Update method
    ypos += speed;
    if (ypos > width) {
      ypos = 0;
    }
    line(0, ypos, width, ypos);
  }
}
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