java-抽象类-练习题

1、【问题描述】定义一个抽象基类Shape，它包含三个抽象方法center()、diameter()、getArea()，从Shape类派生出Square和Circle类，这两个类都用center()计算对象的中心坐标，diameter()计算对象周长，getArea()方法计算对象的面积。编写应用程序使用Rectangle类和Circle类。【输入形式】输入圆的中心坐标、半径；输入正方形中心、边长【输出形式】输出圆的中心坐标、圆周长、圆面积；输出正方形中心坐标、周长、面积【样例输入】【样例输出】please input the circle center:4 4 please input the

2、 circle radius:3 the circle center is (4, 4) the circle diameter is 18.84 the circle area is 28.26 please input thesquare center:5 5 please input the square radius:2the square center is (5,5) the square diameter is 8the square area is 4【样例说明】样例输出中横线是输入。【评分标准】一个测试样例import java.text.DecimalFormat;impo

3、rt java.util.Scanner;public class Test72 public static void main(String args) Scanner scan=new Scanner(System.in); int x,y,r; System.out.println(please input the circle center: ); x=scan.nextInt(); y=scan.nextInt(); System.out.println(please input the circle radius: ); r=scan.nextInt(); Circle circl

4、e = new Circle(r);double area = circle.getArea();double diameter = circle.diameter();System.out.println(the circle center is ( + x + , + y + );System.out.println(the circle diameter is + new DecimalFormat(0.00).format(diameter);System.out.println(the circle area is + new DecimalFormat(0.00).format(a

5、rea); System.out.println(please input the square center: ); x=scan.nextInt(); y=scan.nextInt(); System.out.println(please input the square side length: ); r=scan.nextInt();Rectangle rectangle = new Rectangle(r, r);area = rectangle.getArea();diameter = rectangle.diameter();System.out.println(the squa

6、re center is ( + x + , + y + );System.out.println(the square diameter is + new DecimalFormat(0).format(diameter);System.out.println(the square area is + new DecimalFormat(0).format(area);abstract class Shape public abstract double getArea();class Rectangle extends Shape private double width; private double height; public Rectangle(double width, double height) this.width = width; this.height = height; public double getArea() return width * height;public double diameter() return width + height + width + height; class Circle extends Shape private double r; public Circle(double radius)