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package com.codegym.task.task05.task0517; /* Creating cats */ public class Cat { String name, address, color; int weight, age; public Cat(String name) { this.name = "Bob"; this.age = 4; this.weight = 8; this.color = "Amber"; } public Cat(String name, int weight, int age) { this.name = name; this.age = age; this.weight = weight; this.color = color; } public Cat(String name, int age) { this.name = name; this.age = age; this.weight = weight; this.color = color; } public Cat(int weight, String color) { this.age = age; this.weight = weight; this.color = color; } public Cat(int weight, String color, String address) { this.age = age; this.weight = weight; this.color = color; this.address = "USA, Chicago"; } public static void main(String[] args) { } }

Create the Cat class with five constructors:
- Name,
- Name, weight, age
- Name, age (standard weight)
- Weight, color (name, address, and age are unknown; the cat is homeless)
- Weight, color, address (someone else's pet)

The constructor'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 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 a constructor that takes a name as an argument, but initializes all variables except the address.
The class must have a constructor that takes a name, weight, and age as arguments, and initializes all variables except the address.
The class must have a constructor that takes a name and age as arguments, and initializes all variables except the address.
The class must have a constructor that takes a weight and color as arguments, and initializes all variables except the name and address.
The class must have a constructor that takes a weight, color, and address as arguments, and initializes all variables except the name.

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Guadalupe Gagnon

Level 37 , Tampa, United States

17 December 2018, 14:36

First, for each and every one of the constructors, you need to use the values that are given to you in the constructor to initialize all 5 of the properties: name, address, color, weight, age. The first constructor only gives you name. That means that you need to set this.name = to name. Then you need to put default values (meaning anything that you want) for the other 4 properties that are not passed through the constructor.

public Cat(String name) // this is constructor. the passed variable 'name' needs to be used.
   {
      /*this.name = "Bob";*/
      this.name = name; // this.name is needed so the compiler knows which 'name' is being used, as
      // the constructor has a variable named 'name', and the class has a variable named 'name'
      age = 4;
      weight = 8;
      color = "Amber";
      address = "unknown";
    }

Guadalupe Gagnon

Level 37 , Tampa, United States

17 December 2018, 14:50

So for this one:

public Cat(String name, int age) //2 variables passed in: name and age
    {
        this.name = name; //set property to passed variable 'name'.
        //both of these need 'this' because the variable names are the same as the property names
        this.age = age;
        weight = 8; // set weight to any value, i used 8 as you did in your code
        color = "amber"; // set color to any value, I used the same as you did
        address = "unknown"; // set address to "unknown" as it was not supplied
        // you can set any of these values that aren't supplied to what you want
    }

Guadalupe Gagnon

Level 37 , Tampa, United States

17 December 2018, 14:56

The 'this' keyword is only needed to tell the difference between variables in the constructor to variable in the class (properties) that have the same name. This has to do with variable scope. If you named the variables differently in the constructor you could avoid the 'this' keyword. For example the constructor could look like this:

public Cat(String catName) // changed name to catName
    {
        name = catName; // no conflict in the names, 'this' is not required
        age = 4;
        weight = 8;
        color = "Amber";
        address = "unknown";
    }

Jyothi

Level 20 , United States

17 December 2018, 14:26

You are defaulting Bob in the constructor where name is passed in. you should set this to the parameter passed in. You should only default when the requirement calls for it and there's no parameter passed in the constructor.