identifier expected

Question about the task

Make a family

Java Syntax, Level 8, Lesson 11

Under discussion

Identifier expected error when i try to print the objects, anybody know what is wrong?

1. Create a Human class with String name, boolean sex, int age, and ArrayList<Human> children fields.
2. Create and populate objects so that we end up with: two grandfathers, two grandmothers, one father, one mother, and three children.
3. Display all the Human objects (Hint: use the Human class's toString() method).

Requirements:

The program should display text on the screen.
The Human class must have four fields.
The Human class must have one method.
The Solution class must have one method.
The program should create objects and fill them with data to get two grandfathers, two grandmothers, one father, one mother, and three children. Then it should display all the Human objects on the screen.

package com.codegym.task.task08.task0824; /* Make a family */ import java.util.ArrayList; public class Solution { public static void main(String[] args) { //write your code here Human c1 = new Human("jenny", 12, false, new ArrayList<Human>()); Human c2 = new Human("john", 6, true, new ArrayList<Human>()); Human c3 = new Human("jake", 5, true, new ArrayList<Human>()); ArrayList<Human> children = new ArrayList<>(), father = new ArrayList<>(), mother = new ArrayList<>(); children.add(c1); children.add(c2); children.add(c3); Human f = new Human("Jerry", 50, true, children); Human m = new Human("Bellie", 42, false, children); father.add(f); mother.add(c); Human gf1 = new Human("Jose", 90, true, father); Human gf2 = new Human("June", 80, true, mother); Human gm1 = new Human("Nely", 85, false, father); Human gm2 = new Human("Mellisa", 79, false, mother); } System.out.println(c1.toString()); System.out.println(c2.toString()); System.out.println(c3.toString()); System.out.println(m.toString()); System.out.println(f.toString()); System.out.println(gf1.toString()); System.out.println(gf2.toString()); System.out.println(gm1.toString()); System.out.println(gm2.toString()); public static class Human { //write your code here public String name; public int age; public boolean sex; public ArrayList<Human> children; public Human(String name, int age, boolean sex, ArrayList<Human> children){ this.name = name; this.age = age; this.sex = sex; this.children = children; } public Human(String name, int age, boolean sex){ this.name = name; this.age = age; this.sex = sex; } public String toString() { String text = ""; text += "Name: " + this.name; text += ", sex: " + (this.sex ? "male" : "female"); text += ", age: " + this.age; int childCount = this.children.size(); if (childCount > 0) { text += ", children: " + 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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Nouser

Level 36 , Germany

5 April 2021, 06:37

You're writing code outside of method, directly inside the brackets that belong to the Solution class (starting after the brace in line 32). That is not valid code. Here it's just allowed to define instance and class variables (and declare them if it is done together with the definition). Everything else needs to be in blocks (static block, methods, inner classes). line 25, c isn't defined either. why do we have to make a constructor with all the fields except the ArrayList<Human> children That's not a requirement of the task and therefore you will not have to do that. But it will make your code easier. The functionality of a constructor is to initialize objects when the are created. Name, age and sex you know and that's easy to write. If you add the list to the constructor you'd have to create temp lists in the main with the children add then use that in the constructor. Or you create eg. the mom object and then access the moms children list and add them after the object has been created (in the main).

//like
f.children.add(c1)

Downside is, that you may forget to initialize the list.

John

Level 17 , Mansfield, Philippines

5 April 2021, 08:05

Thank you Nouser ^^

John

Level 17 , Mansfield, Philippines

5 April 2021, 00:08

i knew it, but another question is why do we have to make a constructor with all the fields except the ArrayList<Human> children. looks like its not being used