Question

In Java pls

Part 1 In this section we'll build a small class together, useful for managing a gift card balance. This class will keep track of the total balance and will allow for a starting total, deductions, and a balance report. To manage such details, we'll need a class-level (or instance) variable to store the balance, as well as a few methods to implement the actions mentioned above. Download GiftCard.java and look at the main method. Download the driver GiftCard.java. Add a class-level variable to track the balance at the top of the file. Should this variable be a char? A double? Add a method void setBalance(double newBalance) that resets the balance. Consider making this function fail on negative input Add a deduct(double amount) method that subtracts from the balance Consider making this function fail on a negative balance Add a report() method that prints out the balance remaining on the gift card

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and here is the Giftcard.java

copyable

/////////////////////////////////////////////////////////////////////

/*
* GiftCard.java
*
* Lab 10 Part 1
*
* Authors: Samantha Smith, you
*/
public class GiftCard
{
// Instance Variables
// TODO: balance

// Constructors

/**
* GiftCard(double initialBalance)
*
* Initialize a GiftCard object with a pre-defined amount of money.
*
* @param initialBalance double The desired starting balance
*/
public GiftCard(double initialBalance) {
setBalance(initialBalance);
}

/**
* GiftCard()
*
* Initialize a GiftCard object with a balance of $0.00.
*/
public GiftCard() {}

// Instance Methods
/**
* setBalance
*
* This should set the balance of the gift card to newBalance.
* The balance should be set to zero and complain if the newbalance is less than
* zero.
*
* @param newBalance double The target balance.
*/
public void setBalance(double newBalance) {
// TODO: fill in this method
}

/**
* deduct
*
* This should reduce the balance of the gift card by amount. If the amount is
* negative, complain and leave the balance unchanged. If the new balance is
* negative, complain and leave the balance unchanged.
*
* @param newBalance double The target balance.
*/
public void deduct(double amount) {
// TODO: fill in this method
}

/**
* report
*
* Print the current balance on the card.
*/
public void report() {
// TODO: fill in this method
}

// Driver
public static void main (String[] args) {
GiftCard card0 = new GiftCard();
card0.setBalance(12.00);
card0.report(); // Should print $12.00
card0.deduct(25); // Should complain
card0.report(); // Should print $12.00
card0.deduct(2.50);
card0.report(); // Should print $9.50

GiftCard card1 = new GiftCard(40);
card1.report(); // Should print $40.00
card0.report(); // Should Print $9.50
card1.deduct(20);
card1.deduct(-20); // Should complain
card1.report(); // Should print $20.00

GiftCard card2 = new GiftCard(-20.05); // Should complain
card2.report(); // Should print $0.00
card2.setBalance(15);
card2.report(); // Should print $15.00
card1.report(); // Should print $20.00
card0.report(); // SHould print $9.50
}

}

Answer 1

Please find below the code of the GiftCard class with changes highlighted in bold. It is well explained inside the code using comments.

public class GiftCard {

    private double balance;

    public GiftCard(double initialBalance) {
        // sets the balance
        setBalance(initialBalance);
    }

    public GiftCard() {
    }

    public void setBalance(double newBalance) {
        // if newBalance is negative, display error message to user
        if (newBalance < 0) {
            System.out.println("Balance can't be negative.");
        } else {
            // else set the balance
            balance = newBalance;
        }
    }

    public void deduct(double amount) {
        // if amount is greater than baance, display error message to user
        if (amount > balance) {
            System.out.println("Insufficient Balance!");
        } else if (amount < 0) {
            // if amount is negatice, display error message to user
            System.out.println("Can't deduct negative amount!");
        } else {
            // deduct the amount from balance
            balance -= amount;
        }
    }

    public void report() {
        // display the remaining balance on gift card
        System.out.println("$" + balance);
    }
}

Below is the output that the driver gives:

run $12.0 Insufficient Balance! $12.0 $9.5 $40.0 $9.5 Can't deduct negative amount! $20.0 Balance can't be negative $0.0 $15.0 $20.0 $9.5

This completes the requirement. Let me know if you have any queries.

Thanks!