Thread: Desperate help needed with class and methods

ok so i am looking at my homework for class and i am horribly confused lol. i would greatly appreciate it if someone could help me out with this with a good explanation.

so the instructions are

In this homework, you will write a Car.java file in order to make HW1tester.java (see the attachment) file work. And the output is required to be exactly

This car is Chevy, year 2005, price 3000
This car is Ford, year 2011, price 22000
This car is Audi, year 2012, price 25000
This car is Cadillac, year 2005, price 3000
The total car number is: 4
The total car number is: 4
The total car number is: 4
The total car number is: 4

HW1tester is right here
hw1test.txt

Welcome to the Forum! Please read this topic to learn how to post code correctly and other useful tips for newcomers.

i am horribly confused

We can't help you if we don't know what you're confused about. Describe your confusion or show what code you've managed to write and then explain why you can go no further.

Sorry about that, and thank you for helping me to clean up my post. Basically, my confusion is where to start. I created the Car class, and gave price, brand, and year their separate private classes, but i got stuck when it came to creating the constructor and the methods. Here is the instance code we were given. Note: this IS a homework problem.

public class HW1tester
{
   public static void main(String[] args)
   {
      Car car1 = new Car();
      Car car2 = new Car("Ford", 2013, 20000);
      Car car3 = new Car("Audi", 2012, 25000);
      Car car4 = new Car();
 
      car2.setPrice(22000);
      car2.setYear(2011);
 
      car4.setBrand("Cadillac");
 
      System.out.println("This car is " + car1.getBrand() + ", year " + car1.getYear() + ", price " + car1.getPrice());
      System.out.println("This car is " + car2.getBrand() + ", year " + car2.getYear() + ", price " + car2.getPrice());
      System.out.println("This car is " + car3.getBrand() + ", year " + car3.getYear() + ", price " + car3.getPrice());
      System.out.println("This car is " + car4.getBrand() + ", year " + car4.getYear() + ", price " + car4.getPrice());
 
      System.out.println("The total car number is: " + car1.getNumber());
      System.out.println("The total car number is: " + car2.getNumber());
      System.out.println("The total car number is: " + car3.getNumber());
      System.out.println("The total car number is: " + car4.getNumber());
 
   }
}

You should show us your Car class.
If you look at the main method that you have posted you will see all the methods / constructors that your Car class will need.

public class Car
{
private String brand;
private int year;
private double price;
 
 
 
}

that's about as far as i got and then my brain started jumbling everything up.

Do you know what Getters / Setters are? Because that is what you have to write now.

Perhaps you should Google "Getters / Setter java", I bet you will find good tutorials on this topic, Getters and Setters are quite common.

yes i know these things. i guess what is confusing me is the fact that car1 and car4 have no field initialization. i will begin to try to write a full code once i am on my own laptop and post it here. thanks

--- Update ---

heres what i got:

public class Car
{
private String brand;
private int year;
private double price;
 
 
public Car(String carBrand, int carYear, double carPrice)
{
	brand = carBrand;
	year = carYear;
	price = carPrice;
}
 
public void setBrand(String b)
{
	brand = b;
}
 
public void setYear(int y)
{
	year = y;
}
 
public void setPrice(double p)
{
	price = p;
}
 
 
public String getBrand()
{
	return brand;
}
 
public int getYear()
{
	return year;
}
 
public double getPrice()
{
	return price;
}

the error says:

HW1tester.java:5: error: constructor Car in class Car cannot be applied to given types;
Car car1 = new Car();
^
required: String,int,double
found: no arguments
reason: actual and formal argument lists differ in length


it says the same for car4 as well. not sure what is going on lol.

Your class is almost finished.
The error you get is because you only defined one constructor, your homework requires you to define 2 different constructors.

The one constructor you got is this:

public Car(String carBrand, int carYear, double carPrice)
{
	brand = carBrand;
	year = carYear;
	price = carPrice;
}

it is used in your homework at this point:

      Car car2 = new Car("Ford", 2013, 20000);
      Car car3 = new Car("Audi", 2012, 25000);

But your homework also uses a different constructor, here:

      Car car1 = new Car();
      ...
      ...
      Car car4 = new Car();

You need to define both of them.


There is yet another method that is missing:

      System.out.println("The total car number is: " + car1.getNumber());
      System.out.println("The total car number is: " + car2.getNumber());
      System.out.println("The total car number is: " + car3.getNumber());
      System.out.println("The total car number is: " + car4.getNumber());

As you can see, your car must also provide a method called "getNumber()".

got it. thanks guys for helping. really appreciate it.