java - 简单的Java现值计算器不起作用

我以前没有使用过Java，但对于为什么我编写的简单现值计算器无法正常工作感到困惑。由于某些原因，现值公式会返回一个极小的数字？看看是否可以发现我的错误：

// Import all utilities
import java.text.DecimalFormat;
import java.util.*;

// Base class
public class Project2
{

   // Main function
   public static void main(String[] args)
   {
      // Define variables
      double p = 0.0;
      double f = 0.0;
      double r = 0.0;
      double n = 0.0;
      String another = "Y";

      // Create a currency format
      DecimalFormat dollar = new DecimalFormat("#,###.00");

      // Create a new instance of the scanner class
      Scanner keyboard = new Scanner(System.in);

      // Loop while another equals "Y"
      while(another.equals("Y"))
      {
         // Get future value
         System.out.println("Future value: ");
         f = Double.parseDouble(keyboard.nextLine());

         // Get annual interest rate
         System.out.println("Annual interest rate: ");
         r = Double.parseDouble(keyboard.nextLine());

         // Get Number of years
         System.out.println("Number of years: ");
         n = Double.parseDouble(keyboard.nextLine());

         // Run method to find present value and display result
         p = presentValue(f, r, n);
         System.out.println("Present value: $" + p );

         // Ask if user wants to enter another
         System.out.println("Enter another?(Y/N) ");
         another = keyboard.nextLine().toUpperCase();
      }

   }

   public static double presentValue(double f, double r, double n)
   {
      // Do math and return result
      double p = f / Math.pow((1 + r), n);
      return p;
   }
}

最佳答案

假设您以% per annum的形式输入R，例如R = 4.3%，您希望将函数修改为：

double p = f / (Math.pow((1 + (r/100.0)), n));
return p;

如果这不是您想要的，则可能需要输入R=4.3% p.a的值作为

4.3/100 = 0.043而不是4.3。