如何在 Java 中有效使用模数运算符
我正在用 Java 做一项与货币相关的大学作业。为此，建议我使用整数而不是双精度数，然后在打印报表时将其转换为美元值。
一切工作正常，直到我对数字 4005 进行计算（如 40.05 美元表示为 int）。我正在粘贴我遇到问题的代码部分，如果有人能告诉我我做错了什么，我将不胜感激。
import java.io.*;
class modumess {
public static void main(String[] args) {
int money = 4005; //Amount in cents, so $40.05;
// Represent as normal currency
System.out.printf("$%d.%d", money/100, money%100);
}
}
上面的代码运行时显示 $40.5，而不是 $40.05。什么给？
请注意，这是我的作业，我想学习，所以我非常感谢这里对问题根源的解释，而不仅仅是一个简单的解决方案。
编辑：根据 Finbarr 的回答，我在代码中添加了以下内容，似乎已经解决了问题：
if (money%100 < 10) {
format = "$%d.0%d";
}
这是一个好方法吗？还是我在这里把事情过度复杂化了？
编辑：我只是想澄清一下，芬巴尔和韦斯的回答都对我有帮助，我接受了韦斯的回答，因为它让我更清楚如何继续。
I am doing a college assignment in Java that deals with currency. For that I am advised to use ints instead of doubles and then later convert it to a dollar value when I print out the statement.
Everything works fine until I do calculations on the number 4005 (as in $40.05 represented as an int). I am pasting the part of code I am having problems with, I would appreciate if someone could tell me what I am doing wrong.
import java.io.*;
class modumess {
public static void main(String[] args) {
int money = 4005; //Amount in cents, so $40.05;
// Represent as normal currency
System.out.printf("$%d.%d", money/100, money%100);
}
}
The above code, when run, shows $40.5, instead of $40.05. What gives?
Kindly note that this is for my homework and I want to learn, so I would really appreciate an explanation about the root of the problem here rather than just a simple solution.
EDIT: Following Finbarr's answer, I have added the following to the code which seems to have fixed the problem:
if (money%100 < 10) {
format = "$%d.0%d";
}
Is this a good way to do it or am I over-complicating things here?
EDIT: I just want to make it clear that it was both Finbarr and Wes's answer that helped me, I accepted Wes's answer because it made it clearer for me on how to proceed.
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（2）
对于一般情况，更好的方法是这样的：
%02d为 2 位数字提供 0 填充。这样你就不需要额外的 if 语句。有关可以使用格式执行的操作的更多说明，请参阅此内容： http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Formatter.html#syntax
A better way would be something like this for a general case:
%02dgives you 0 padding for 2 digits. That way you don't need the extra if statement.See this for more explanation of things you can do in format: http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Formatter.html#syntax
模运算符返回除法后的余数，而不进行小数计算。在本例中，4005%100 返回 5，因为 4005/100 的余数为 5。
The modulus operator returns the remainder after division without fractional calculation. In this case, 4005%100 returns 5 as the remainder of 4005/100 is 5.