public class Test {
    public static void main(String[] args) {
        // 创建不同图形对象
        Shape circle = new Circle(3);
        Shape rect = new Rectangle(4, 5);
        Shape triangle = new Triangle(3, 4, 5);

        // 统一调用工具类打印面积
        System.out.println("圆形：");
        ShapeUtil.printArea(circle);

        System.out.println("矩形：");
        ShapeUtil.printArea(rect);

        System.out.println("三角形：");
        ShapeUtil.printArea(triangle);
    }
}