Dart class example

dar_class_example.dart

class Point {
  // num is the parent class of `double` and `int`.
  num x;
  num y;
  num z;
  /**
   * This is like
   * Point(num x, num y, num z) {
       this.x = x;
       this.y = y;
       this.z = z;
     }
   */
  Point(this.x, this.y, this.z);
  
  /* This is named constructor! to use multiple constructor.
   * We can not unfortunately do Poin(this.x) NOOO
   * instead Point.origin(this.x) where "origin" is any name!
   * and when instanting we may use new Point.origin()
   * and of course that ignores the first constructor from above ^^.
   */
  Point.origin(this.x);
}

void main() {
  // Point point = new Point(); // or
  // var point = new Point();
  //var point = new Point.origin(4);
  var point = new Point(4, 5, 6);
  point.x = 8;
  print(point is Point);
  print(point);
  print(point.x);
  print(point.y);
  print(point.z);
}