Eclipse上的Java编译错误

Question

So I'm working on this program and I've created two classes, one class called CreditCard, the other called CreditCardTester.I'm using Eclipse IDE and I keep getting compiling errors such as "The method getBalance(double) in the type CreditCard is not applicable for the arguments ()". I'm not really sure on what I have to fix.

This is the first class called CreditCard:

public class CreditCard
{
private String accountNumber;
private double creditLimit;
private double balance;

public void CreditCard(String number, double limit)
{
    accountNumber = number;
    limit = creditLimit;
    balance = 0;
}

public String getAccountNumber() 
{
    return accountNumber;
}

public double getCreditLimit() 
{
    return creditLimit;
}

public double getBalance(double theBalance) 
{
    return balance;
}

public double charge(double amount)
{
    balance = balance + amount;

    return balance;
}

This is the second class CreditCardTester:

public class CreditCardTester
{


public static void main(String[] args) 
{
    CreditCard card = CreditCard("1234-5678-9012-3456", 1000.00);

    String formatString = "Credit Card [number = %s, bal = %.2f, limit = %.2f]\n";

    System.out.printf(formatString, card.getAccountNumber(), card.getBalance(), card.getCreditLimit());

    System.out.println("\nCharging $50.00 to credit card...\n");

    card.charge(50.00);

    System.out.printf(formatString, card.getAccountNumber(), card.getBalance(), card.getCreditLimit());
}

Answer 1

This is not a constructor, because you added void , making it a normal method:

public void CreditCard(String number, double limit)

Remove void :

public CreditCard(String number, double limit)

Also, one of the assignments in the method/constructor is backwards. You assigned the instance variable to the parameter.

limit = creditLimit;

Change it around:

creditLimit = limit;

You're missing "new" when creating a CreditCard :

CreditCard card = CreditCard("1234-5678-9012-3456", 1000.00);

Try

CreditCard card = new CreditCard("1234-5678-9012-3456", 1000.00);

You have an unused parameter on the getBalance method, and you call it without a parameter.

public double getBalance(double theBalance) 

Remove it:

public double getBalance() 

Answer 2

I think getBalance should not accept an argument in your class definition.

Use this in your CreditCard class:

public double getBalance() 
{
    return balance;
}