Learn dart language as Java Developers

Bicycle.dart

class Bicycle {
  int cadence;
  int _speed = 0; // Private
  int gear;

  Bicycle(this.cadence, this.gear);
  
  int get speed => _speed; // Getter
  
  void applyBreake(int dec) {
    _speed -= dec;
  }
  
  void speedUp(int inc) {
    _speed += inc;
  }
  
  @override
  toString() => 'Bicycle: $_speed mph';
}

void main() {
  var bike = Bicycle(2, 1);
  bike.speedUp(5);
  bike.applyBreake(1);
  print(bike);
}

Rectangle.dart

import 'dart:math';

class Rectangle {
  
  Point origin;
  int width;
  int height;

  // Using opotional params (Like overloading in Java)
  Rectangle({
    this.origin = const Point(0, 0),
    this.width = 0,
    this.height = 0
  });
  
  @override
  String toString() =>
      'Origin: (${origin.x}, ${origin.y}), width: $width, height: $height';
}

void main() { 
  print(Rectangle(origin: const Point(10, 20), width: 100, height: 200));
  print(Rectangle(origin: const Point(10, 10)));
  print(Rectangle(width: 200));
  print(Rectangle());
}

Shape.dart

import 'dart:math';

abstract class Shape {
  num get area;
}

class Circle implements Shape {
  final num radius;
  Circle(this.radius);
  num get area => pi * pow(radius, 2);
}

class Square implements Shape {
  final num side;
  Square(this.side);
  num get area => pow(side, 2);
}

void main() {
  final circle = Circle(2);
  print(circle.area);
  
  final square = Square(2);
  print(square.area);
}