class  SavingsAccount{
	static double annualInterestRate;
	private double savingsBalance;

	SavingsAccount(double Balance){
		savingsBalance=Balance;
	}
	void calculateInterest(int n){
		for (int i=1;i<=n;i++){
			savingsBalance+=savingsBalance*SavingsAccount.annualInterestRate;
		}
	}
	
	double getSavingBalance()
	{
		return savingsBalance;
	}

	static void modifyInterestRate(double rate){
		annualInterestRate=rate;
	}
}

public class Ex040204{
	public static void main(String[] args){
		SavingsAccount saver1=new SavingsAccount(2000.00);
		SavingsAccount saver2=new SavingsAccount(3000.00);
		SavingsAccount.modifyInterestRate(0.04);
		saver1.calculateInterest(8);
		saver2.calculateInterest(8);
		System.out.println("儲戶1 8年的儲蓄額："+saver1.getSavingBalance());
		System.out.println("儲戶2 8年的儲蓄額："+saver2.getSavingBalance());

		SavingsAccount.modifyInterestRate(0.05);
		saver1.calculateInterest(2);
		saver2.calculateInterest(2);
		System.out.println("儲戶1 2年的儲蓄額："+saver1.getSavingBalance());
		System.out.println("儲戶2 2年的儲蓄額："+saver2.getSavingBalance());
		
	}
}