so hard task i try solve it alredy 15.days i believe.

Question about the task

Under discussion

i dont understand @overide . and this task just piss me off. because why they overode inside methode sustem method. dont understand how it works.

Task: Each cat has a name and a mother.
Create a class that describes this situation.
Create two objects: a daughter cat and a mother.
Display them on the screen.

New task: Each cat has a name, a father, and a mother.
Edit Cat so that it reflects these relationships.
Create 6 objects: grandfather (the father's father), grandmother (the mother's mother), father, mother, son, daughter.
Display them all in the following order: grandfather, grandmother, father, mother, son, daughter.

Example input:
Grandfather Tiger Grandmother Puss Father Oscar Mother Missy Son Simba Daughter Coco

Example output:
The cat's name is Grandfather Tiger, no mother, no father The cat's name is Grandmother Puss, no mother, no father The cat's name is Father Oscar, no mother, Grandfather Tiger is the father The cat's name is Mother Missy, Grandmother Puss is the mother, no father The cat's name is Son Simba, Mother Missy is the mother, Father Oscar is the father The cat's name is Daughter Coco, Mother Missy is the mother, Father Oscar is the father

Requirements:

The program should read in the names of 6 cats in the specified order.
The main method should create 6 Cat objects.
The program should display 6 lines with information about the cats.
The line about the grandfather (first line) must match the conditions.
The line about the grandmother (second line) must match the conditions.
The line about the father (third line) must match the conditions.
The line about the mother (fourth line) must match the conditions.
The line about the son (fifth line) must match the conditions.
The line about the daughter (sixth line) must match the conditions.

package com.codegym.task.task06.task0621; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* Cat relations */ public class Solution { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String grandfatherName = reader.readLine(); Cat catGrandfather = new Cat(grandfatherName, null, null); String grandmotherName = reader.readLine(); Cat catGrandmother = new Cat(grandmotherName, null, null); String fatherName = reader.readLine(); Cat catFather = new Cat(fatherName, null, catGrandfather); String motherName = reader.readLine(); Cat catMother = new Cat(motherName, catGrandmother, null); String sonName = reader.readLine(); Cat catSon = new Cat(sonName, catMother , catFather); String daughterName = reader.readLine(); Cat catDaughter = new Cat(daughterName, catMother , catFather); /* // ||** start of comment **|| String grandfatherName = reader.readLine(); Cat catGrandfather = new Cat(grandfatherName); String grandmotherName = reader.readLine(); Cat catGrandmother = new Cat(grandmotherName); String fatherName = reader.readLine(); Cat catFather = new Cat(fatherName); String motherName = reader.readLine(); Cat catMother = new Cat(motherName); String sonName = reader.readLine(); Cat catSon = new Cat(sonName); String daughterName = reader.readLine(); Cat catDaughter = new Cat(daughterName); */ System.out.println(catGrandfather); System.out.println(catGrandmother); System.out.println(catFather); System.out.println(catMother); System.out.println(catSon); System.out.println(catDaughter); } public static class Cat { private String name; private Cat father; private Cat mother; Cat(String name) { this.name = name; } Cat(String name, Cat mother, Cat father) { this.name = name; this.mother = mother; this.father = father; } @Override public String toString() { String st = ""; /* if (name.equals("Grandfather Tiger")) System.out.println("The cat's name is " + name + " no mother, no father"); if (name.equals("Grandmother Puss")) System.out.println("The cat's name is " + name + " no mother, no father"); if (name.equals("Father Oscar")) System.out.println("The cat's name is " + name + " no mother, Grandfather Tiger is the father"); if (name.equals("Mother Missy")) System.out.println("The cat's name is " + name + ", Grandmother Puss is the mother, no father"); if (name.equals("Son Simba")) System.out.println("The cat's name is " + name + ", Mother Missy is the mother, Father Oscar is the father"); if (name.equals("Daughter Coco")) System.out.println("The cat's name is " + name + ", Mother Missy is the mother, Father Oscar is the father"); return ""; // System.out.print(""); */ // coment } // System.out.println(name, catGrandfather.name); // ||** comment code **|| /* if (father == null && mother == null) { System.out.println("The cat's name is " + name + " no mother, no father"); } if ( father != null && mother == null) { System.out.println("The cat's name is " + name + ", " + mother + " is mother, no father"); } if ( father == null && mother != null) { System.out.println("The cat's name is " + name + ", no mother, " + father + " is the father"); } if ( father != null && mother != null) { System.out.println("The cat's name is " + name + ", " + mother + " is mother, " + father + " is thefather"); } */ System.out.println (catFather); return st; } // ||** end of comment **|| } }

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Gellert Varga

Level 23 , Szekesfehervar, Hungary

3 November 2021, 19:22

If you write this:

System.out.println(dogObject);

then by default the reference (memory address) of the object is printed. Every object is a descendant of the Object class. Objects of your Dog class inherit the toString method from the Java Object class. So even if you don't write a toString method in your Dog class, you can still use the toString method on your dogObject. The dogObject has toString method. The System.out.println command - before printing - automatically calls the toString method on the dogObject passed to it. By default (inherited from the Object class), toString will return the reference of the object, so that's what will be printed. You have the option to write a toString method in the Dog class that you want. You don't want to see the reference of the object when issuing a Sys.o.print command, you want to see the name of the dogObject, its age, its father's name, etc. For this purpose you have to override the inherited toString method. It means You have to place a toString method in your Dog class, for example like this:

public String toString() {
    return "Name is: " + this.name + ", age=" + this.age + ", its father is: " + this.father.name;
}

As Lupe wrote: it is not required to use the @Override keyword. The overriding works without it. The use of the word "this" is not strictly necessary, too. If you have further questions, feel free to use the "Reply" button, I'll try to answer (if I can.)

Guadalupe Gagnon

Level 37 , Tampa, United States

2 November 2021, 21:02

The @Override is designed to create a compile time error that will be highlighted by the IDE when it is added to a method that does not over ride anything. This is very useful when creating applications where you create a class with methods that are supposed to over ride methods from a parent class but don't actually do that. Can save hours of bug tracking. With this in mind, the @Override tag does nothing more and is not required Java code.

Guadalupe Gagnon

Level 37 , Tampa, United States

2 November 2021, 21:19

Methods are required to have a few things: - an access modifier (eg public, private, protected, or even none which is default to protected) - a return value (e.g. String, int, void) - a method name (e.g println, nextLine, toString) - and method parameters, which are the values between the parentheses. The problem that I see from the commented out code is that it is printing directly from the toString() method, however the toString() method has String declared as its return value which means that it MUST return a String to the point where the method is called. That String should be what the code is trying to print in the commented code. So, instead of something like this:

System.out.println("The cat's name is " + name + ", no mother, " + father + " is the father");

It should be:

return "The cat's name is " + name + ", no mother, " + father + " is the father";

for all cases.