dart class

                                    // entry point
void main(){

  // using the Dog class - creating an instance of this class
  var myDog = Dog();
  
  // assigning values to the newly clreated instance
  myDog.breed = 'Poodle';
  myDog.name = 'Jack';
  myDog.color = 'Brown';
 
  // displaying the values on the console 
  print(myDog.breed);
  print(myDog.name);
  print(myDog.color);
}

// Dog class 
class Dog{

  // class properties
  String breed;
  String name;
  String color;
}

                                    // You cannot mutate final variables in a constructor body, 
// instead you must use a special syntax.
// Also note if you have a super() call, it must be called last.
class Point {
  final num x;
  final num y;
  final num distanceFromOrigin;

  // Special syntax
  Point(this.x, this.y) :
    distanceFromOrigin = sqrt(pow(x, 2) + pow(y, 2));
}

                                    if (emp is Person) {
  // Type check
  emp.firstName = 'Bob';
}