Abstract class

main.dart

void main() {
  Car car1 = Car("Car1");
  car1.go();
  car1.sayHello();
}

abstract class Vehicule {
  final String name;
  
  Vehicule(this.name);
  void sayHello() {
    print("Hello from Vehicule");
  }
  
  void go() {
    print("Go from Vehicule");
  }
}

class Car extends Vehicule {
  Car(String name): super(name);
  
  @override
  void sayHello() {
    print("Hello from Car");
  }
}