如何在单独的方法中进行计算，然后将它们发送回main进行打印？

Question

我正在尝试为另一种方法的兴趣进行计算，并且我知道我必须在main之外创建另一个方法然后将返回结束，但我不知道如何标题这个新方法和如何在那里进行计算。我认为这是令我困惑的while循环。我曾经在一个不同的项目上做过一次这样的事情，所以我知道如何做到这一点，但是这个项目与其他项目不同，我并不是真的理解它。任何帮助都非常受欢迎，因为我已经在这方面工作了很长时间，只是想完成它。提前致谢。

import java.util.Scanner; // This allows for the use of the scanner in the class

public class SavingsAccount // Start of class
{
    public static void main(String[]args) // Start of main
    {
        double P; // These store the amounts that will be used in the accruing interest formula
        double i;
        double n;
        double S = 0;
        int timesLooped = 0;
        Scanner readConsole = new Scanner(System.in); // This is the scanner

        System.out.println("I am a savings account interest calculator."); // Prompts the user for input
        System.out.println("How much money have you deposited?");
        P = readConsole.nextDouble();
        S = P;
        System.out.println("Now, what is the annual interest rate? (i.e. .05)");
        i = readConsole.nextDouble();
        System.out.println("Finally, how long do you plan on having the money in the account?");
        n = readConsole.nextDouble();
        while (timesLooped <= n)
        {
            S = S + (P * i);
            timesLooped += 1;
        }
        System.out.println("Your balance in that time span is " + S + "."); // Tells you your ending balance
    }

}

Answer 1

根据您的评论，我认为您想要这个：

private static double addInterest(double S, double P, double i)
{
    return S + (P * i);
}

...

public static void main()
{
    ...
    while (timesLooped <= n)
    {
        S = addInterest(S, P, i);
    }

修改

我为了好玩而做了一些小改进：

1. 我将整个兴趣计算放入函数中并使用取幂而不是循环。
2. 我给变量提供了更具描述性的名称。
3. 我使用System.out.format打印结果。

以下是代码：

private static double computeCompoundInterest(double principal, double rate,
                                              double years) {
    return principal * Math.pow(1 + rate, years);
}

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

    System.out.println("I am a savings account interest calculator.");

    System.out.println("How much money have you deposited?");
    double principal = scanner.nextDouble();

    System.out.println("Now, what is the annual interest rate? (i.e. .05)");
    double rate = scanner.nextDouble();

    System.out.println("How many years will you hold that money in the account?");
    double years = scanner.nextDouble();

    double total = computeCompoundInterest(principal, rate, years);

    System.out.format("Your balance at the end of that period will be %.2f.\n", years, total);
}