java源碼-題目求源碼，不太會寫，求源碼⋯⋯

題目求源碼，不太會寫，求源碼⋯⋯

⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯

最佳回答：

僅供參考

public class ShapeTest {

    abstract class Shape{
        public abstract double area();
        public abstract double perimeter();
    }

    class Rect extends Shape{

        private double width;
        private double length;

        public Rect(double w,double l){
            width = w;
            length = l;
        }
        @Override
        public double area() {
            return width*length;
        }

        @Override
        public double perimeter() {
            return 2*(width+length);
        }
    }

    class Circle extends Shape{

        private double r;
        public Circle(double r){
            this.r = r;
        }
        @Override
        public double area() {
            return Math.PI * r * r;
        }

        @Override
        public double perimeter() {
            return 2 * Math.PI * r;
        }
    }
    public static void main(String[] args){

        ShapeTest st = new ShapeTest();

        Rect r = st.new Rect(2,3);
        System.out.println("矩形的周長為："+r.perimeter());
        System.out.println("矩形的面積為："+r.area());

        Circle c = st.new Circle(1); //單位圓
        System.out.println("圓形的周長為："+c.perimeter());
        System.out.println("圓形的面積為："+c.area());
    }
}