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40// DIFFERENCE BETWEEN ABSTRACT CLASSES AND INTERFACE CLASSES
// abstract classes are used to provide a base class for concrete
// subclasses to inherit from, while interfaces are used to define
// a set of methods that a class must implement
abstract interface class Shape { // abstract interface creates true interface
double calculateArea();
}
// Circle class implementing the Shape interface
class Circle implements Shape {
double radius;
Circle(this.radius);
@override
double calculateArea() {
return 3.14 * radius * radius;
}
}
// Rectangle class implementing the Shape interface
class Rectangle implements Shape {
double width;
double height;
Rectangle(this.width, this.height);
@override
double calculateArea() {
return width * height;
}
}
// AreaCalculator class now accepts shapes that implement the Shape interface
class AreaCalculator {
double calculateArea(Shape shape) {
return shape.calculateArea();
}
}