package?com.demo; public?class?Test{ /** ?*?@param?args ?*/ public?static?void?main(String[]?args)?{ System.out.println("請輸入矩形的長和寬："); Shape?rec?=??new?Rectangle(); rec.ciru(); rec.area(); System.out.println("請輸入圓的半徑："); Shape?cir?=?new?Circular(); cir.area(); cir.ciru(); } }以下是全部代碼package?com.demo; public?abstract?class?Shape?{ ??abstract?void?ciru();//周長 ??abstract?void?area();//面積 }package?com.demo; import?java.util.Scanner; public?abstract?class?Rectangle?extends?Shape?{ Scanner?input?=?new?Scanner(System.in); int?length?=?input.nextInt(); int?width?=?input.nextInt(); @Override void?ciru()?{ //?TODO?Auto-generated?method?stub System.out.println("矩形的周長是："?+?2*(length?+?width)); } @Override void?area()?{ //?TODO?Auto-generated?method?stub System.out.println("矩形的面積是："?+?length*width); } }package?com.demo; import?java.util.Scanner; public?abstract?class?Circular?extends?Shape?{ static?double?PI?=?3.14; Scanner?input?=?new?Scanner(System.in); int?r?=?input.nextInt(); @Override void?ciru()?{ //?TODO?Auto-generated?method?stub System.out.println("圓的周長為："?+?2*PI*r); } @Override void?area()?{ //?TODO?Auto-generated?method?stub System.out.println("圓的面積為："?+?PI*r*r); } }package?com.demo; public?class?Test{ /** ?*?@param?args ?*/ public?static?void?main(String[]?args)?{ System.out.println("請輸入矩形的長和寬："); Shape?rec?=??new?Rectangle(); rec.ciru(); rec.area(); System.out.println("請輸入圓的半徑："); Shape?cir?=?new?Circular(); cir.area(); cir.ciru(); } }