Question

所以我被分配为我的编程类编写一个程序，提示用户并将输入的值读取为double（最大输入为[99.99]九十九美元，九十九美分），这将代表一个货币金额。然后，我要确定代表所述金额所需的每张账单和硬币的最少数量（10美元的钞票是所需的最大尺寸）。

我遇到了四舍五入的问题。例如，输入99.99将返回3便士，当它应该是4便士。我的老师明确告诉我，不要超越课堂上的材料（只有创建扫描仪，转换数据类型和转换。这意味着没有BigDecimal）。任何帮助将不胜感激。

import java.util.Scanner;

public class MoneyConversion
{
     public static void main(String[] args)
     {
          //Set variables for input, dollars, and cents
          double inputAmount, change;
          int tens, fives, ones;
          int quarters, dimes, nickels, pennies;

          //Create scanner to setup for user input
          Scanner scan = new Scanner(System.in);

          //Scan user input and store into double
          System.out.print("Enter monetary amount: ");
          inputAmount = scan.nextDouble();

          //Extract demical or cent amount from dollar amount
          change = (inputAmount - (int) inputAmount) * 100;

          System.out.println("That's equivalent to:");

          //Extract and print denomination for ten-dollar bills
          tens = (int) inputAmount / 10;
          inputAmount = inputAmount % 10;
          System.out.println(tens + " ten dollar bills");

          //Extract and print denomination for five-dollar bills
          fives = (int) inputAmount / 5;
          inputAmount = inputAmount % 5;
          System.out.println(fives + " five dollar bills");

          //Extract and print denomination for one-dollar bills
          ones = (int) inputAmount;
          System.out.println(ones + " one dollar bills");

          //Extract and print denomination for quarters
          quarters = (int) change / 25;
          change = change % 25;
          System.out.println(quarters + " quarters");

          //Extract and print denomination for dimes
          dimes = (int) change / 10;
          change = change % 10;
          System.out.println(dimes + " dimes");

          //Extract and print denomination for nickels
          nickels = (int) change / 5;
          change = change % 5;
          System.out.println(nickels + " nickels");

          //Convert value for change to integer value and print for pennies
          pennies = (int) change;
          System.out.println(pennies + " pennies");

     }

}

Answer 1

你最好将数字转换为整数（便士的数量）并根据它进行计算，因为这样你可以避免你现在遇到的浮点错误的类型（它们是由将浮点数表示为二进制）。

如果您逐步使用this（您需要对输入进行硬编码才能使用它），您可以看到错误。

由于第20行的舍入，更改金额设置为98.99999999999949，这就是为什么缺少一分钱

Java Money面额舍入问题

1 个答案: