PTA4-6题目集总结与归纳

import java.util.Scanner;

class Main {

    public static void main(String[] args) {
        int inType;
        Scanner scanner = new Scanner(System.in);
        inType = scanner.nextInt();
        switch (inType) {
            case 1:       //圆类，输入半径，输出面积
                double r = scanner.nextDouble();      //半径r
                if (r < 0.0) {
                    System.out.println("Wrong Format");
                } else {
                    Circle circle = new Circle();    //circle：圆
                    circle.setRadius(r);
                    System.out.println(String.format("Circle‘s area:%.2f", circle.getArea()));
                }
                break;


            case 2:         //矩形类，输入宽和长，输出面积
                double width = scanner.nextDouble();    //宽
                double length = scanner.nextDouble();   //长
                if (width < 0.0 || length < 0.0) {
                    System.out.println("Wrong Format");
                } else {
                    Rectangle rectangle = new Rectangle();  //rectangle：矩形
                    rectangle.setLength(length);
                    rectangle.setWidth(width);
                    System.out.println(String.format("Rectangle‘s area:%.2f", rectangle.getArea()));
                }
                break;
            case 3:   //球类，输入半径，输出表面积和体积
                double r2 = scanner.nextDouble();      //球半径r2
                if (r2 < 0.0) {
                    System.out.println("Wrong Format");
                } else {
                    Ball ball = new Ball();       //ball：球
                    ball.setRadius(r2);
                    System.out.println(String.format("Ball‘s surface area:%.2f", ball.getArea()));
                    System.out.println(String.format("Ball‘s volume:%.2f", ball.getVolume()));
                }
                break;
            case 4:      //立方体类，输入宽，长，高，输出表面积和体积
                double width2 = scanner.nextDouble();      //宽
                double length2 = scanner.nextDouble();     //长
                double height = scanner.nextDouble();      //高
                if (width2 < 0.0 || length2 < 0.0 || height < 0.0) {
                    System.out.println("Wrong Format");
                } else {
                    Box box = new Box();     //box：盒子，立方体
                    box.setHeight(height);
                    box.setWidth(width2);
                    box.setLength(length2);
                    System.out.println(String.format("Box‘s surface area:%.2f", box.getArea()));
                    System.out.println(String.format("Box‘s volume:%.2f", box.getVolume()));
                }
                break;
            default:
                System.out.println("Wrong Format");
        }
    }
}
class Shape //定义一个无自身属性，有一个返回值为0.0的求面积方法
{

    public Shape()
    {
        System.out.println("Constructing Shape");
    }
    public double getArea()
    {
        return 0.0;
    }
}

class Circle extends Shape//继承自Shape    圆
{
    public Circle()       //圆
    {
        System.out.println("Constructing Circle");
    }
    private double radius;//新定义一个半径

    public void setRadius(double radius) {// 设置半径
        this.radius = radius;
    }

    public double getRadius() {// 获取半径
        return radius;
    }
    public double getArea() {     //求圆的面积：π*r*r
        return Math.PI*radius*radius;        //Math.PI是π
    }

}
class Rectangle extends Shape            //矩形
{
    public Rectangle()
    {
        System.out.println("Constructing Rectangle");
    }
    private double width;
    private double length;
    public double getWidth() {
        return width;
    }

    public void setWidth(double width) {
        this.width = width;
    }

    public double getLength() {
        return length;
    }

    public void setLength(double length) {
        this.length = length;
    }
    public double getArea() {        //矩形的面积：a*b
        return width*length;
    }
}
class Ball extends Circle                //球
{
    private double radius2;

    public Ball()
    {
        System.out.println("Constructing Ball");
    }
    public void setRadius(double radius2) {// 设置半径
        this.radius2 = radius2;
    }

    public double getRadius() {// 获取半径
        return radius2;
    }
    public double getArea() {        //球的表面积：4*π*r*r
        return 4.0*Math.PI*radius2*radius2;
    }
    public double getVolume()      //球的体积：4/3  * π * r的立方
    {
        double r2=getRadius();
        return 4.0/3.0*r2*r2*r2*Math.PI;
    }

}
class Box extends Rectangle             //立方体
{
    public Box()
    {
        System.out.println("Constructing Box");
    }
    private double height;
    public double getHeight() {
        return height;
    }
    public void setHeight(double height) {
        this.height = height;
    }
    public double getVolume()         //求立方体的体积a*b*c
    {
        return height*super.getArea();
    }

    public double getArea() {              //求立方体的表面积2*（a*b+a*c+b*c）
        double w2=getWidth();
        double l2=getLength();
        return 2*(w2*l2+w2*height+l2*height);
    }


}