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Question about the task

Initializing cats

Java Syntax, Level 5, Lesson 7

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It feels like I have tried everything to satisfy conditions and nothing seems to work. Please advise. Thank you.

Create a Cat class with five initializers:
- Name,
- Name, weight, age
- Name, age (standard weight)
- Weight, color (unknown name, address and age, i.e. a homeless cat)
- Weight, color, address (someone else's pet)

The initializer's job is to make the object valid.
For example, if the weight is unknown, then you need to specify some average weight.
A cat can't weigh nothing.
The same applies to age and color.
But there may or may not be a name (i.e. name might be null).
The same applies to the address (it might be null).

Requirements:

The program must not read data from the keyboard.
The Cat class must have a String variable name.
The Cat class must have an int variable age.
The Cat class must have an int variable weight.
The Cat class must have a String variable address.
The Cat class must have a String variable color.
The class must have an initialize method that takes a name as an argument, but initializes all variables except the address.
The class must have an initialize method that takes a name, weight, and age as arguments, but initializes all variables except the address.
The class must have an initialize method that takes a name and age as arguments, and initializes all variables except the address.
The class must have an initialize method that takes a weight and color as arguments, and initializes all variables except the name and address.
The class must have an initialize method that takes a weight, color, and address as arguments, but initializes all variables except the name.

package com.codegym.task.task05.task0510; /* Initializing cats */ public class Cat { //write your code here String name = "unknown"; int weight = 8; int age = 0; String color = "undetermined"; String address = "null"; public void initialize (String name){ this.name = name; this.weight = 7; this.age = 4; this.color = "grey"; } public void initialize (String name, int weight, int age){ this.name = "Kitty"; this.weight = 7; this.age = 4; this.color = "grey"; } public void initialize (String name, int age){ this.name = "Kitty"; this.weight = 7; this.age = 4; this.color = "grey"; } public void initialize (int weight, String color){ this.weight = 7; this.age = 4; this.color = "grey"; } public void initialize (int weight, String color, String address){ this.weight = 7; this.age = 4; this.color = "grey"; this.address = "123 Main St."; } public static void main(String[] args) { } }

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Mysnikol Miller

Level 7 , Lutsen, United States

30 July 2020, 14:38

Unfortunately, I had to give up on this one and copy someone else's answer. I have yet to understand why my code did not work. There were no errors and I did everything the same as the answer I used. Oh well, no learning on this task.

PGT

Level 23 , Warsaw, Poland

30 July 2020, 13:13

Hi, the problem you are facing has actually nothing to do with amount of constructors, because you have set up them well. But when you create initialize method like:

public void initialize (String name, int weight, int age){
        this.name = "Kitty";
        this.weight = 7;
        this.age = 4;
        this.color = "grey";
}

You have to initialize name, weight and age to variables in similar way to this:

public void initialize (String name, int weight, int age){
        this.name = name;
        this.weight = weight;
        this.age = age;
        this.color = "grey";
}

Just set up the rest accordingly to the example above. :P Good luck :)

Mysnikol Miller

Level 7 , Lutsen, United States

30 July 2020, 14:06

I do not understand why this.name = name but this.color = "grey". As I said I tried all these variations to no success. this.name = "Kitty", this.name = name, this.name; (I do not understand why all of these are not valid).

Justin Johnson

Level 17 , New Orleans, United States

30 July 2020, 14:21

When you initialize the Cat field, the String name and String address are allowed to be null. So for these, you do not need to declare them. Just keep them as "VariableType variableName;". When you don't declare these fields, their default value is set to null. When you initialize your public void methods, you only need to initialize whatever the parameter holds. For example, public void initialize(String name) {}, you only need to initialize the String name (this.name = name;). Do not include any other initialize statements. Apply, this structure to the rest of your methods.

PGT

Level 23 , Warsaw, Poland

30 July 2020, 14:31

Ah, okay. If you don't understand then I will try to explain it as properly as I can :P So the basic idea of creating initialize method is to create Cat with a certain values as default and certain new. Let's say that you want to create a cat. At the beginning if u think properly a Cat CANNOT weight null or be invisible - that's why you create default fields as weight = 5; (because statistically most cats weight 5, but ofc it's just a basic approach not the real statistical data) or you can just say that most cats are blue/black/yellow, but none of them is invisible! :D Which is why you need to create so many initializers. Let's look at this one:

public void initialize (int weight, String color){
    this.weight = weight;
    this.age = 4;
    this.color = color;
}

Here you can see that you didn't do anything with name and address because realistically speaking not every cat has a name or always had one and same goes to address, because a cat is just homeless. But you can see here that if you want to call this method you need to give two information: (int weight, String color) which means obviously weight and color. So that's why you instantly put them to variables this.weight and this.color. You don't need to use default values here since someone by using this method instantly gives them for you. On the other hand you lack an age in the parameters of the method and cat cannot be ageless, every cat lived for some time. That is why you use just a default value in the method since noone gave you particular information about age. :) By the way: By using "this." you refer to the fields in Cat Class, but without it when you have it in parameters of the method you refer to them. :)