使用Java在for循环之外返回值时遇到问题

Question

返回for语句之外的值时遇到问题。在下面的语法中，我必须在for循环之外声明finalAmount变量，因为如果我不这样做，它将无法工作。返回值是0，这是我不想要的。在Java中，如何在for循环语句之外使用变量

谢谢

import java.util.Scanner;

public class CompundInterest2 {
    public static void main(String[] args){
        Scanner input = new Scanner(System.in);

        double amount, rate, year;

        System.out.println("What is the inital cost? Dude");
        amount = input.nextDouble();
        System.out.println("What is the interest rate?");
        rate = input.nextDouble();
        rate = rate/100;
        System.out.println("How many years?");
        year = input.nextDouble();

        input.close();


        justSayit(year, rate, amount);

    }

    private static double thefunction(double amount, double rate, double year){
        double finalAmount = 0;  // This is where I'm running into trouble. If I don't declare this variable the program won't work. But if I declare it, it works but returns 0.
        for(int x = 1; x < year; x++){
            finalAmount = amount * Math.pow(1.0 + rate, year); 
        }
        return finalAmount;
    }

    public static void justSayit(double year, double rate, double amount){
        double awesomeValue = thefunction(amount, year, rate);
        System.out.println("For " + year + " years an initial " + amount + 
                " cost compounded at a rate of " + rate + " will grow to " + awesomeValue); 
    }

Answer 1

我想你应该把所有的金额都加起来

for(int x = 1; x < year; x++){
  finalAmount += amount * Math.pow(1.0 + rate, year); // += 
}

另外，对thefunction的justSayit函数调用不正确-

double awesomeValue = thefunction(amount, rate, year); /* not amount, year, rate */

Answer 2

for循环中的代码的问题在于它不依赖于循环变量x，所以很可能是您忘记了什么，或者循环没有用

Answer 3

问题是，当您调用函数时，它的参数顺序错误：

double awesomeValue = thefunction(amount, year, rate);

该方法以订单金额、费率、年份为准