procedural || data structure - clean code book

procedural || data structure - clean code book

void main() {
  Square s = Square();
  s.width = 10;
  s.topLeft = Point(0,0);
  
  print(Geometery.area(s));
  print(Geometery.perimeter(s));
}

class Point{
  int x,y;
    Point(this.x,this.y);
}

class Square{
  Point topLeft;
  double width;
}

class Rectangle{
  Point topLeft;
  double width;
  double height;
}

class EquilateralTriangle{
  Point topHead;
  double side;
  double height;
}


class Circle{
  Point centerPoint;
  double radius;
}

class Geometery{
  static final double PI = 3.1465165465;
  
  static double area(Object shape){
    if(shape is Square){
      return shape.width * shape.width;
    }else if(shape is Rectangle){
      return shape.width * shape.height;
    }else if(shape is Circle){
      return PI * shape.radius * shape.radius;
    }else if(shape is EquilateralTriangle){
      return .5 * shape.side * shape.height;
    }
    throw Exception();
  }
  
  static double perimeter(Object shape){
    if(shape is Square){
      return shape.width * 4;
    }else if(shape is Rectangle){
      return (shape.width + shape.height) * 2;
    }else if(shape is Circle){
      return 2 * PI * shape.radius;
    }else if(shape is EquilateralTriangle){
      return shape.side * 3;
    }
    throw Exception();
  }
}