银行利息 Q

Posted 2023-02-22

【中文标题】银行利息 Q

【英文标题】：Banking interest Q

【发布时间】：2017-10-19 14:54:26

【问题描述】：

我正在尝试制作一个程序，用本金、利率和年数计算帐户的复利。我试图用对话框来做这件事/如果原则留给积累，程序会输出投资回报。

我卡在计算部分，请帮忙

package firstAssignment;

import java.util.Scanner;

import javax.swing.JOptionPane;

public class thinkingQuestion 

public static void main(String[] args) 

//Banking program that asks user for the amount of money they wish to invest in a 
//compound interest account (principle), the interest rate (percent value) and the time frame (years).

    Scanner in= new Scanner(System.in);

    String principle, interestVal, years;
    int newPrinciple,newYears;
    double total;

        principle=JOptionPane.showInputDialog("How much money would you like to invest?");

        interestVal=JOptionPane.showInputDialog("What's the interest rate?");   

        years=JOptionPane.showInputDialog("How many years?");

        //convert from String to integer

        newPrinciple=Integer.parseInt(principle);
        newYears=Integer.parseInt(years);

        double newInterestVal=Integer.parseInt(interestVal);

        total=JOptionPane.PLAIN_MESSAGE(newPrinciple*Math.pow(1+ newInterestVal, newYears), newYears);

【问题讨论】：

我特别卡在总计部分，因为它不允许我使用兴趣公式来解决问题。

total= newPrinciple*Math.pow((1+newInterestVal), newYears); JOptionPane.showMessageDialog (null, total+"", "Total", JOptionPane.INFORMATION_MESSAGE);您还必须输入复利期数 n。这里我假设 n=1

它显示将字符串转换为 int 的错误，尤其是第 31 行

【参考方案1】：

我删除了一些你不需要的变量，我认为主要问题在于显示消息的 java 语法。在这里你可以看到一个教程：

https://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

import javax.swing.JOptionPane;

public class InterestBanking 

    public static void main(String[] args) 

        // Banking program that asks user for the amount of money they wish to
        // invest in a
        // compound interest account (principle), the interest rate (percent
        // value) and the time frame (years).

        String principle, interestVal, years;
        float newPrinciple, newYears;

        principle = JOptionPane.showInputDialog("How much money would you like to invest?");

        interestVal = JOptionPane.showInputDialog("What's the interest rate?");

        years = JOptionPane.showInputDialog("How many years?");

        // convert from String to integer

        newPrinciple = Float.parseFloat(principle);
        newYears = Float.parseFloat(years);

        double newInterestVal = Float.parseFloat(interestVal);

        //You could change your calculation here if this isn't the need formula
        double interest = newPrinciple * Math.pow(1 + newInterestVal, newYears);

        //you were assigning the result to a total variable. That's not neccesary
        JOptionPane.showMessageDialog(null, "Interest:" + NumberFormat.getCurrencyInstance(new Locale("en", "US")).format(interest) + " In years: " + newYears);
    

【讨论】：

它在测试时显示错误，它说它正在将字符串转换为双行或整数行。

你用的是哪个版本的java？

eclipse kepler，我学校不让我们用高版本

在窗口菜单上转到首选项 > java > 编译器。告诉我哪个是编译器合规级别

编译器级别为1.4