程序中存取款方法的问题

Question

Saver 1
New Monthly Savings Balance After Interest: 27958.33
Saver 2
New Monthly Savings Balance After Interest: 4933.33
Saver 1
New Monthly Savings Balance After Interest: 49240.28
Saver 2
New Monthly Savings Balance After Interest: 6431.11

再次感谢您！

public class SavingsAccountDriver {

    public static void main(String[] args) {
        SavingsAccount saver1 = new SavingsAccount();
        SavingsAccount saver2 = new SavingsAccount();
        
        saver1.setsavingsBalance(2000);
        saver2.setsavingsBalance(3000);
        
        SavingsAccount.modifyInterestRate(0.04);
        
        saver1.calculateMonthlyInterest();
        saver2.calculateMonthlyInterest();
        
        System.out.printf("\nSaver 1\nNew Monthly Savings Balance After Interest: %.2f",saver1.getsavingsBalance());
        System.out.printf("\nSaver 2\nNew Monthly Savings Balance After Interest: %.2f",saver2.getsavingsBalance());
        
        SavingsAccount.modifyInterestRate(0.05);
        
        saver1.calculateMonthlyInterest();
        saver2.calculateMonthlyInterest();

        System.out.printf("\nSaver 1\nNew Monthly Savings Balance After Interest: %.2f",saver1.getsavingsBalance());
        System.out.printf("\nSaver 2\nNew Monthly Savings Balance After Interest: %.2f",saver2.getsavingsBalance());
    }

public class SavingsAccount {
    
    public static double annualInterestRate;
    public double savingsBalance;
    
    /*
     * Constructor
     * */
    public SavingsAccount() {
        annualInterestRate = 0;
        savingsBalance = 0;
    }
    /*
     * Overloaded
     * */
    public SavingsAccount(double savingsBalance) {
        this.savingsBalance = savingsBalance;
    }
    /*
     * Calculates Monthly Interest from savings balance and interest rate
     * */
    public void calculateMonthlyInterest() {
        savingsBalance += savingsBalance*annualInterestRate/12;
    }
    /*
     * Interest Rate modifier
     * */
    public static void modifyInterestRate(double newInterestRate) {
        annualInterestRate = newInterestRate;
    }
    /*
     * Returns new Savings Balance
     * */
    public double getsavingsBalance() {
        return savingsBalance;
    }   
    /*
     * Sets new savings balance after interest
     * */
    public void setsavingsBalance(double savingsBalance) {
        this.savingsBalance = savingsBalance;
    }

    /*
     * Returns Interest Rate
     * */
    public double getannualInterestRate() {
        return annualInterestRate;
    }
}

public class SpecialSavings extends SavingsAccount {
    
    public SpecialSavings() {
        annualInterestRate = 0;
        savingsBalance = 0;
    }   
    
    public SpecialSavings(double savingsBalance) {
        super(savingsBalance);
    }
    
    public void calculateMonthlyInterest() {
        if(getsavingsBalance()>10000) {
            modifyInterestRate(10);
        }else {
            modifyInterestRate(4);
        }
        super.calculateMonthlyInterest();
    }
    
    public void deposit(double amount) {
        savingsBalance+=amount;
    }
    
    public void withdraw(double amount) {
        savingsBalance-=amount;
    }
    
}

public class SpecialSavingsDriver {

    public static void main(String[] args) {
        SpecialSavings saver1 = new SpecialSavings();
        SpecialSavings saver2 = new SpecialSavings();
        
        saver1.setsavingsBalance(2000);
        saver2.setsavingsBalance(3000);
        
        SavingsAccount.modifyInterestRate(0.04);
        
        saver1.deposit(13000);
        saver1.deposit(250);
        saver2.deposit(350);
        saver2.deposit(350);
        
        saver1.calculateMonthlyInterest();
        saver2.calculateMonthlyInterest();
        
        System.out.printf("\nSaver 1\nNew Monthly Savings Balance After Interest: %.2f",saver1.getsavingsBalance());
        System.out.printf("\nSaver 2\nNew Monthly Savings Balance After Interest: %.2f",saver2.getsavingsBalance());
        
        saver1.withdraw(1000);
        saver1.withdraw(100);
        saver2.withdraw(100);
        saver2.withdraw(10);
        
        saver1.calculateMonthlyInterest();
        saver2.calculateMonthlyInterest();
        
        System.out.printf("\nSaver 1\nNew Monthly Savings Balance After Interest: %.2f",saver1.getsavingsBalance());
        System.out.printf("\nSaver 2\nNew Monthly Savings Balance After Interest: %.2f",saver2.getsavingsBalance());

    }

}

Answer 1

我觉得问题出在这条线上。

保存平衡*年度间战略/12；

它将像这样执行：-

(savingsBalance*annualInterestRate)/12;
= (multipliedValue)/12;
= result

savingsBalance*(annualInterestRate/12);