首先，应从类GeoObjects继承一个类矩形。 其次，应从类矩形继承类广场。
给出了抽象类GeoObjects。
abstract class GeoObjects{
public abstract double Perimeter();
public abstract double Surface();
public static void main (String [] argv){
double width = 4.0, height = 5.0, side= 3.0;
GeoObject rectangle = new Rectangle (width, height);
GeoObject square= new Square(side);
System.out.println ("Perimeter = " + rectangle.Perimeter());
System.out.println ("Surface= " + rectangle.Surface());
System.out.println ("Perimeter= " + square.Perimeter());
System.out.println ("Surface= " + square.Surface());
}
}
class Rectangle extends GeoObjects{
double width, height, side;
Rectangle (double width, double height){
this.width = width;
this.height= height;
}
public double Perimeter (){
return 2*(width+ height);
}
public double Surface(){
return width* height;
}
}
class Square extends Rectangle {
double side;
Square (double side){
this.side= side;
}
public double Perimeter (){
return 4*side;
}
public double Surface(){
return side*side;
}
}
我得到了编译器信息，即Square构造函数与Rectangle变量具有不同数量的变量。
答案 0 :(得分：5)
编译器错误消息通知您，您正在尝试使用与构造函数具有不同数量的参数来调用__REACT_ERROR_OVERLAY_GLOBAL_HOOK__中的超类构造函数。您没有在startReportingRuntimeErrors中显式调用超类构造函数，因此编译器已在Rectangle中插入了对默认超类构造函数的调用-有效地Square作为{{1}中的第一行}。
但是Rectangle中没有没有参数的构造函数；只有一个带有2个参数。通过两次将super();传递到Square()来适当地调用它。
您还将注意到，Rectangle和side方法不再需要被覆盖，因为它们现在将使用超类中的正确值。
此外，常规的Java方法命名约定会让您以小写字母开头的方法命名为super()和Perimeter。
答案 1 :(得分：1)
要修复Square类，您将需要使用SELECT MAX(br1.id) /* Get last update of bonus */,
br1.uid,
br1.name,
rb1.instance_id,
rb1.player_id,
br1.redeem_count,
rb1.executed,
rb1.completed,
rb1.canceled
FROM
bonus_records br1
LEFT JOIN
redeemed_bonuses rb1 ON
rb1.bonus_id = br1.id
WHERE
(rb1.player_id IS NULL) OR /* never redeemed */
(rb1.player_id = 1 AND /* if redeemed then */
(
br1.redeem_count > ( /* total count of X redemed bonus is less then redeem_count but redeem_count <> 0 */
SELECT COUNT(*)
FROM redeemed_bonuses rb2
INNER JOIN bonus_records br2 ON rb2.bonus_id = br2.id
WHERE br2.uid = br1.uid AND rb2.completed = 0 AND rb2.canceled = 0
) OR
br1.redeem_count = 0 /* redeem_count = 0 means that there is no established limit of redeem */
)
)
GROUP BY
br1.uid
从super(side, side)调用构造函数。您将不再需要Square内的side class变量，可以将其简化为：
平方：
Rectangle矩形：
class Square extends Rectangle {
Square (double side){
super(side,side);
}
}
如果要重载Rectangle中的方法或将实现特定功能的方法放置为平方，则需要使用class Rectangle extends GeoObjects{
double width, height;
Rectangle (double width, double height){
this.width = width;
this.height= height;
}
public double Perimeter (){
return 2*(width+ height);
}
public double Surface(){
return width* height;
}
}
和width变量而不是side。