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Dart / Flutter myNotes
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| import 'dart:math'; | |
| /* | |
| abstract class Shape { | |
| num get area; | |
| } | |
| */ | |
| abstract class Shape { | |
| factory Shape(String type) { | |
| if (type == 'circle') return Circle(2); | |
| if (type == 'square') return Square(2); | |
| throw 'Can\'t create $type.'; | |
| } | |
| num get area; | |
| } | |
| class CircleMock implements Circle { | |
| num area; | |
| num radius; | |
| } | |
| 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); | |
| } | |
| Shape shapeFactory(String type) { | |
| if (type == 'circle') return Circle(2); | |
| if (type == 'square') return Square(2); | |
| throw 'Can\'t create $type.'; | |
| } | |
| main() { | |
| // final circle = Circle(3.45); | |
| // final square = Square(5); | |
| /* | |
| final circle = shapeFactory('circle'); | |
| final square = shapeFactory('square'); | |
| */ | |
| final circle = Shape('circle'); | |
| final square = Shape('square'); | |
| print(circle.area); | |
| print(square.area); | |
| } |
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| import 'dart:math'; | |
| class Rectangle { | |
| int width; | |
| int height; | |
| Point origin; | |
| Rectangle({this.origin = const Point(0, 0), this.width = 0, this.height = 0}); | |
| @override | |
| String toString() => | |
| 'Origin: (${origin.x}, ${origin.y}), width: $width, height: $height'; | |
| } | |
| main() { | |
| print(Rectangle(origin: const Point(10, 20), width: 100, height: 200)); | |
| print(Rectangle(origin: const Point(10, 10))); | |
| print(Rectangle(width: 200)); | |
| print(Rectangle()); | |
| } |
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| import 'dart:math'; | |
| | |
| abstract class Shape { | |
| num get area; | |
| } | |
| | |
| class Circle implements Shape { | |
| final num radius; | |
| Circle(this.radius); | |
| num get area => pi * pow(radius, 2); | |
| } | |
| | |
| class Square implements Shape { | |
| final num side; | |
| Square(this.side); | |
| num get area => pow(side, 2); | |
| } | |
| | |
| main() { | |
| final circle = Circle(3.45); | |
| final square = Square(5); | |
| print(circle.area); | |
| print(square.area); | |
| } |
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| String scream(int length) => "A${'a' * length}h!"; | |
| main() { | |
| final values = [1, 2, 3, 5, 10, 50]; | |
| for (var length in values) { | |
| print(scream(length)); | |
| } | |
| // OR | |
| values.map(scream).forEach(print); | |
| // OR | |
| values.skip(1).take(3).map(scream).forEach(print); | |
| } |
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