java - 如何在我的类中设置要调用到方法中的值“Present Value”

Question

我目前正在尝试从FutureValue方法中提取PresentValue方法的返回值进行计算。

我尝试通过声明 pv1 并仅使用该值来解决该问题。新的问题是它被设置为 0。

有谁知道我如何解决这个问题或者至少能够使用从当前值返回的值？

public class Bank1 {

    private double cash;
    private double rate = .0425;
    private int years;

    public Bank1(double cash, int years){
        this.cash = cash;
        this.years = years;     
    }

    private double pv1 = cash/Math.pow((1+rate), years);

    public double PresentValue(){
        double pv = cash/Math.pow((1+rate), years);
        double present = Math.round(pv *100);
        present = present/100;
        return present;
    }


    public double  FutureValue(){
        double fv = pv1*Math.pow((1+rate), years);
        double future = Math.round(fv *100);
        future = future/100;
        return future;
    }   

}

输出只是对方法的调用。

我收到的输出是

你想拥有多少钱？100

您的投资有多少年？ 1

100.0 美元是您想要的金额。

95.92 美元是您需要投资的金额

0.0 美元将是您的 future 值(value)

感谢您的帮助!!

Answer 1

只需更改pv1*Math.pow((1+rate), 年);

对于 this.PresentValue()*Math.pow((1+rate), 年);

public class Bank1 {

private double cash;
private double rate = .0425;
private int years;

public Bank1(double cash, int years){
    this.cash = cash;
    this.years = years;     
}

private double pv1 = cash/Math.pow((1+rate), years);

public double PresentValue(){
    double pv = cash/Math.pow((1+rate), years);
    double present = Math.round(pv *100);
    present = present/100;
    return present;
}


public double  FutureValue(){
    double fv = this.PresentValue()*Math.pow((1+rate), years);
    double future = Math.round(fv *100);
    future = future/100;
    return future;
}   

public static void main(String args[]){
    Bank1 bank = new Bank1(100.0, 1);
    System.out.println("PresentValue: " + bank.PresentValue());
    System.out.println("FutureValue: " + bank.FutureValue());
}

}