Classes - Object oriented programming

main.dart

void main() {
  //new instance of class
  MyNewClass myNewClass = new MyNewClass();
  var anotherInstance = new MyNewClass();
  print(myNewClass.runtimeType);
  anotherInstance.sayHello();
  
  Rectangle rectangle1 = new Rectangle(20, 30);
  print(rectangle1.runtimeType);
  print(rectangle1.perimeter());
  rectangle1.showPerimeter();
  
  rectangle1.length = 43;
  rectangle1.showPerimeter();
  
  rectangle1.breadth = 50;
  rectangle1.showPerimeter();
  
  var square1 = new Square(35);
  print(square1.runtimeType);
  print(square1.perimeter());
  square1.showPerimeter();
  
  Rectangle(20, 20).showPerimeter();
  Square(20).showPerimeter();
  
  // Circle(radius: 66).showPerimeter();
}


class MyNewClass {
  void sayHello() {
    print("hello");
  }
}

class Rectangle {
  int length;
  int breadth;
  Rectangle(this.length, this.breadth);
  
  int perimeter() {
    return 2 * (length + breadth);
  }
  
  void showPerimeter() {
    print("Perimeter is ${perimeter()}");
  }
}

class Square{
  int length;
  Square(this.length);
  
  int perimeter() {
    return 4 * length;
  }
  
  void showPerimeter() {
    print("Perimeter is ${perimeter()}");
  }
}

//Inheritance
/*
class Square extends Rectangle{
  Square(int size) : super(size, size);
}

class Circle extends Rectangle{
  Circle({@required int radius}) : super(radius, radius);
  @override int perimeter() {
    return (2 * length * 3.14).toInt();
  }
}
*/