example of using classes

class_example

Ball b1, b2, b3, b4;

void setup() {
  size(400, 400);
  b1 = new Ball();
  b2 = new Ball();
  b3 = new Ball();
  b4 = new Ball();
}

void draw() {
  background(255);
  b1.display();
  b1.go();
  b1.reflect();
  
  b2.display();
  b2.go();
  b2.reflect();
  
  b3.display();
  b3.go();
  b3.reflect();
  
  b4.display();
  b4.go();
  b4.reflect();
  
}


class Ball {
  float x, y, diametr;
  float speedX, speedY;

  Ball() {
    x = random(0, width);
    y = random(0, height);
    diametr = random(5, 60);
    speedX = random(1, 3);
    speedY = random(1, 3);
  }

  void display () {
    ellipse(x, y, diametr, diametr);
  }

  void go() {
    x = x + speedX;
    y = y + speedY;
  }

  void reflect() {
    if (x < 0 || x > width) speedX = - speedX;
    if (y < 0 || y > height) speedY = - speedY;
  }
}