java-抽象类-练习题

【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】pleaseinputthecirclecenter:44pleaseinputthecircleradius:3thecirclecenteris(4,4)thecirclediameteris18.84thecircleareais28.26pleaseinputthesquarecenter:55pleaseinputthesquareradius:2thesquarecenteris(5,5)thesquarediameteris8thesquareareais4【样例说明】样例输出中横线是输入。【评分标准】一个测试样例importjava.text.DecimalFormat;importjava.util.Scanner;publicclassTest72{publicstaticvoidmain(String[]args){Scannerscan=newScanner(System.in);intx,y,r;System.out.println(pleaseinputthecirclecenter:);x=scan.nextInt();y=scan.nextInt();System.out.println(pleaseinputthecircleradius:);r=scan.nextInt();Circlecircle=newCircle(r);doublearea=circle.getArea();doublediameter=circle.diameter();System.out.println(thecirclecenteris(+x+,+y+));System.out.println(thecirclediameteris+newDecimalFormat(0.00).format(diameter));System.out.println(thecircleareais+newDecimalFormat(0.00).format(area));System.out.println(pleaseinputthesquarecenter:);x=scan.nextInt();y=scan.nextInt();System.out.println(pleaseinputthesquaresidelength:);r=scan.nextInt();Rectanglerectangle=newRectangle(r,r);area=rectangle.getArea();diameter=rectangle.diameter();System.out.println(thesquarecenteris(+x+,+y+));System.out.println(thesquarediameteris+newDecimalFormat(0).format(diameter));System.out.println(thesquareareais+newDecimalFormat(0).format(area));}}abstractclassShape{publicabstractdoublegetArea();}classRectangleextendsShape{privatedoublewidth;privatedoubleheight;publicRectangle(doublewidth,doubleheight){this.width=width;this.height=height;}publicdoublegetArea(){returnwidth*height;}publicdoublediameter(){returnwidth+height+width+height;}}classCircleextendsShape{privatedoubler;publicCircle(doubleradius){this.r=radius;}publicdoublegetArea(){return3.14*r*r;}publicdoublediameter(){return3.14*2*r;}}