[Dart] Class - Method override

Method override & super kewword

 

void main() {
  // Method overriding
  Parent parent = new Parent(3);
  Child child = new Child(3);
  
  print('parent.cal():' + parent.cal().toString());
  print('child.cal():' + child.cal().toString());
}

class Parent {
  final int _number;
  
  Parent(this._number);
  
  int cal() {
    return this._number * this._number;
  }

}

class Child extends Parent {
  Child(int number) : super(number);
  
  @override
  int cal(){                # @ 키워드를 부모의 함수를 재정의
    return super.cal() * 2; # super 키워드를 이용해서 부모의 함수를 사용
  }
}

--------------------------------------------[result]

parent.cal():9
child.cal():18