这是哪里出了问题？

有关任务的问题

构建家庭

Java 语法, 第 8 级, 课程 11

已解决

哪里错了？

1.创建包含 String name、boolean sex、int age 和 ArrayList<Human> children 字段的 Human 类。
2.创建并填充对象，以便我们最终得到：两个祖父、两个祖母、一个父亲、一个母亲和三个孩子。
3.显示所有 Human 对象（提示：使用 Human 类的 toString() 方法）。

要求：

程序应在屏幕上显示文本。
Human 类必须包含四个字段。
Human 类必须包含一个方法。
Solution 类必须包含一个方法。
程序应创建对象并用数据填充它们，以得到两个祖父、两个祖母、一个父亲、一个母亲和三个孩子。然后，程序应在屏幕上显示所有 Human 对象。

package zh.codegym.task.task08.task0824; /* 构建家庭 */ import java.util.ArrayList; public class Solution { public static void main(String[] args) { //在此编写你的代码 ArrayList<Human> humans=new ArrayList<>(); humans.add(new Human("zufu1",true,78)); humans.add(new Human("zufu2",true,78)); humans.add(new Human("zumu1",false,78)); humans.add(new Human("zumu2",false,78)); humans.add(new Human("fuqin",true,28)); humans.add(new Human("muqin",false,28)); humans.add(new Human("haizi1",false,8)); humans.add(new Human("haizi2",false,8)); humans.add(new Human("haizi3",false,8)); System.out.println(humans); } public static class Human { //在此编写你的代码 String name; boolean sex; int age; ArrayList<Human> children =new ArrayList<>(); public Human(String name,boolean sex,int age){ this.name=name; this.sex=sex; this.age=age; } public Human(String name,boolean sex,int age,ArrayList<Human> list){ this(name, sex, age); this.children =list; } public String toString() { String text = ""; text += "名字：" + this.name; text += "，性别：" + (this.sex ? "男" : "女"); text += "，年龄：" + this.age; int childCount = this.children.size(); if (childCount > 0) { text += "，孩子：" + this.children.get(0).name; for (int i = 1; i < childCount; i++) { Human child = this.children.get(i); text += "，" + child.name; } } return text; } } }

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xiaowu

级别 16 ，shenzhen

8 六月 2022, 04:00

public static void main(String[] args) { //在此编写你的代码 ArrayList<Human> human1 = new ArrayList<Human>(); //父亲 ArrayList<Human> human2 = new ArrayList<Human>(); //母亲 ArrayList<Human> human3 = new ArrayList<Human>(); //三个孩子 ArrayList<Human> human4 = new ArrayList<Human>(); //孩子这一代没有孩子 Human father = new Human("父亲",true,45,human3); human1.add(father); Human mother = new Human("母亲",false,43,human3); human2.add(mother); Human grandFather = new Human("外祖父",true,65,human2); Human grandMother = new Human("外祖母",false,65,human2); Human grandFather1 = new Human("祖父",true,65,human1); Human grandMother1 = new Human("祖母",false,65,human1); Human child1 = new Human("孩子1",true,15,human4); Human child2 = new Human("孩子2",false,13,human4); Human child3 = new Human("孩子3",true,11,human4); human3.add(child1); human3.add(child2); human3.add(child3); System.out.println(grandFather); System.out.println(grandMother); System.out.println(grandFather1); System.out.println(grandFather1); System.out.println(father); System.out.println(mother); System.out.println(child1); System.out.println(child2); System.out.println(child3); }

AE86

级别 20 ，Jinan

20 七月 2020, 08:31

import java.util.List; import java.util.ArrayList; /* 构建家庭 */ public class Solution { public static void main(String[] args) { //在此编写你的代码 ArrayList<Human> children4 = new ArrayList<>();//孩子这一代没有孩子 ArrayList<Human> children1 = new ArrayList<>();//三个孩子 ArrayList<Human> children2 = new ArrayList<>();//父亲 ArrayList<Human> children3 = new ArrayList<>();//母亲 Human h1 = new Human("小明",true,15,children4); children1.add(h1); Human h2 = new Human("小红",false,12,children4); children1.add(h2); Human h3 = new Human("小王",true,13,children4); children1.add(h3); Human father =new Human("父亲",true,40,children1); children2.add(father); Human mother = new Human("母亲",false,38,children1); children3.add(mother); Human Grandfather1 = new Human("外祖父",true,80,children3); Human Grandmother1 = new Human("外祖母",false,78,children3); Human grandfather = new Human("祖父",true,82,children2); Human grandmother = new Human("祖母",false,80,children2); System.out.println(h1); System.out.println(h2); System.out.println(h3); System.out.println(father); System.out.println(mother); System.out.println(grandmother); System.out.println(grandfather); System.out.println(Grandmother1); System.out.println(Grandfather1); } public static class Human { //在此编写你的代码 String name; boolean sex; int age; ArrayList<Human> children = new ArrayList<Human>(); public Human(String name,boolean sex,int age,ArrayList<Human>children){ this.name =name; this.sex =sex; this.age =age; this.children = children; }

Raisenkei

级别 9 ，Occhiobello，Italy

2 六月 2020, 09:21

自己看吧，我觉得这样更好懂

Raisenkei

级别 9 ，Occhiobello，Italy

2 六月 2020, 09:03

public static void main(String[] args) { //在此编写你的代码 ArrayList<Human> childrenOfChildren = new ArrayList<>(); Human children1 = new Human("Alex",true,10,childrenOfChildren); Human children2 = new Human("Lux",false,8,childrenOfChildren); Human children3 = new Human("Alessandro",true,5,childrenOfChildren); ArrayList<Human> children = new ArrayList<>(); children.add(children1); children.add(children2); children.add(children3); Human mother = new Human("Anna",false,30,children); Human father = new Human("Pixis",true,35,children); ArrayList<Human> childrenBigger1 = new ArrayList<>(); childrenBigger1.add(father); ArrayList<Human> childrenBigger2 = new ArrayList<>(); childrenBigger2.add(mother); Human grandFather1 = new Human("Alan",true,70,childrenBigger1); Human grandMother1 = new Human("ALexa",false,70,childrenBigger1); Human grandFather2 = new Human("Pepe",true,70,childrenBigger2); Human grandMother2 = new Human("Pyke",false,70,childrenBigger2); System.out.println(grandFather1); System.out.println(grandFather2); System.out.println(grandMother1); System.out.println(grandMother2); System.out.println(father); System.out.println(mother); System.out.println(children1); System.out.println(children2); System.out.println(children3); } public static class Human { //在此编写你的代码 String name; boolean sex; int age; ArrayList<Human> children; public Human(){ } public Human(String name, boolean sex, int age,ArrayList<Human> children){ this.name = name; this.sex = sex; this.age = age; this.children = children; } }

Harry

级别 15 ，Singapore，Singapore

1 六月 2020, 13:35

The children instance variable is unused when creating new objects such as father, mother and grandfather.

曌

级别 20 ，Changchun，China

1 六月 2020, 13:50

能否再具体点？我想这样写，但是好像还是不太对 public Human(String name,boolean sex,int age){ this.name=name; this.sex=sex; this.age=age; children.add(this); }

Harry

级别 15 ，Singapore，Singapore

1 六月 2020, 14:16

Suppose a father has 2 children, Tom and Sam. In the first step, we create two Human objects for Tom and Sam respectively. For Tom and Sam, in the constructor we just need to initialize the children instance variables using empty ArrayList. In the second step, we create a Human object to be the father. Since he is the father of Tom and Sam, when initializing his instance variable children , we need to create an ArrayList and add Tom and Sam to it. Only in this way, other objects can know that the father has two children. According to your code, I would suggest to add the variable children to the current constructor and follow Step 1 and 2 to resolve the issue.

曌

级别 20 ，Changchun，China

1 六月 2020, 14:23

十分感谢你的耐心解答

Harry

级别 15 ，Singapore，Singapore

1 六月 2020, 16:01

Glad to be of help:)