package w4; public class ShapeUtil { public static void printArea(Shape shape) { System.out.println("该图形的面积为:" + shape.getArea()); } public static void main(String[] args) { Shape circle = new Circle(5); printArea(circle); Shape rectangle = new Rectangle(4, 6); printArea(rectangle); Shape triangle = new Triangle(3, 8); printArea(triangle); } }