Thread: How to call a constructor in main

Hey guys, I am trying to call a constructor from PrepaidCard class in my main method, but I am not sure how to proceed.

As seen below, both the PrepaidCard constructor and the setCardID method have the ability to set the card ID.

public class PrepaidCard
{
        public PrepaidCard(String id, int token)
	{
		cardID = id;
		tokenBalance = token;
	}
        public void setCardID(String id, int token)
	{
		cardID = id;
		tokenBalance = token;
	}
}

Now in this block of code, I can successfully pass the id and token value by calling the setCardID method from the PrepaidCard class.
Now I would like to call the PrepaidCard constructor from the PrepaidCard class to pass the id and token value, instead of using the setCardID method.

public class PrepaidCardTest
{
	public static void main(String[] args)
	{
		PrepaidCard card2 = new PrepaidCard(id, token);
 
                System.out.print("Enter Card2 cardID: ");
		id = input.nextLine();
		card2.setCardID(id, token);
        }
}

Does anyone know how to call the PrepaidCard constructor from the PrepaidCard class, to successfully pass the id and token value, in my main method?
Specifically how to modify or replace this line of code so that it can correctly call the PrepaidCard constructor?

card2.setCardID(id, token);

Thanks for your reply and reminder of cross posting.
I have omitted the declaration of the variables, but if you want, I can update the code to make it compile.
Do you know how to call the PrepaidCard constructor from the PrepaidCard class? So that I won't have to call the setCardID method, or is it not possible to call a constructor like that?
I would like to replace the setCardID method with the PrepaidClass constructor to pass the id and token, or is it not possible to do that and I have to use the setCardID method? Because in my assignment, it only supplies the PrepaidCard constructor and not the setCardID method.
Both of these (PrepaidCard constructor and setCardID method) are in the PrepaidCard class. If I can successfully pass the id and token to the PrepaidCard constructor, then I can delete the setCardID method as it is of no use.

Post the PrepaidCard class.

This is the PrepaidCard class.

public class PrepaidCard
{
        private String cardID;
	private int tokenBalance;
 
        public PrepaidCard(String id, int token)
	{
		cardID = id;
		tokenBalance = token;
	}
        public void setCardID(String id, int token)
	{
		cardID = id;
		tokenBalance = token;
	}
}

Originally Posted by GregBrannon

Post the PrepaidCard class.

You're getting compiler errors, right? What are they and what have you tried to do to correct them?

I compile the program fine, just that I would like to call the PrepaidCard constructor instead of calling the setCardID method.
Do you know if it is possible to do that?

Originally Posted by GregBrannon

You're getting compiler errors, right? What are they and what have you tried to do to correct them?

Like this:

public static void main(String[] args)
{
    // initialize id
 
 
    // initialize token
 
 
    PrepaidCard card2 = new PrepaidCard(id, token);
 
} // end method main()

To call the constructor of the `PrepaidCard` class in your `main` method, you need to use the `new` keyword followed by the class name and parameters required by the constructor. In this case, the constructor of `PrepaidCard` takes two parameters: `id` and `token`. Here's how you can modify the line of code to call the constructor instead of the `setCardID` method:

```java
PrepaidCard card2 = new PrepaidCard(id, token);
```

This line of code creates a new instance of the `PrepaidCard` class, invoking its constructor with the provided `id` and `token` values. After this line, you don't need to call the `setCardID` method because the constructor has already initialized the `cardID` and `tokenBalance` fields with the specified values. So, you can remove the following line:

```java
card2.setCardID(id, token);
```

With these changes, your main method should correctly initialize a new PrepaidCard object. If you need further assistance with Java assignments, there are many resources available online, such as programminghomeworkhelp.com, where you can find help with Java assignment.