java - 如何在税收程序[Java]中四舍五入？

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How to round a number to n decimal places in Java
                                
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我需要将输出浮到小数点后两位，因为输出就是金钱。例如，如果我运行：


  如果您单身，请输入1。如果您已结婚，请输入2
  
  1个
  
  输入您的应税收入
  
  27060.34
  
  联邦所得税：$ 4060.3435


我需要联邦所得税来输出$ 4060.34而不是$ 4060.3435

我的代码：

import static org.junit.Assert.*;
import java.util.Scanner;
import org.junit.Test;
public class IRS {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter 1 if you are single. Enter 2 if you are married");
        int martialstatus = scan.nextInt();
        if (martialstatus == 1) {
            Scanner scan2 = new Scanner(System.in);
            System.out.println("Enter your taxable income");
            double income = scan2.nextDouble();
            if ((income > 0) && (income <= 27050.00)) {
                System.out.println("Federal Income Tax:$" + (income * .15));
            }
            if ((income > 27050.00) && (income <= 65550.00)) {
                System.out.println("Federal Income Tax:$" + (4057.50 + (.275 * (income - 27050))));
            }
            if ((income > 65550.00) && (income <= 136750.00)) {
                System.out.println("Federal Income Tax:$" + (14645.00 + (.305 * (income - 65550.00))));
            }
            if ((income > 136750.00) && (income <= 297350.00)) {
                System.out.println("Federal Income Tax:$" + (36361.00 + (.355 * (income - 136750.00))));
            }
            if (income > 297350.00) {
                System.out.println("Federal Income Tax:$" + (93374.00 + (.391 * (income - 297350.00))));
            }
        } else if (martialstatus == 2) {
            Scanner scan3 = new Scanner(System.in);
            System.out.println("Enter your taxable income");
            double income2 = scan3.nextDouble();
            if (income2 <= 45200.00) {
                System.out.println("Federal Income Tax:$" + (.15 * income2));
            }
            if ((income2 > 45200.00) && (income2 <= 109250.00)) {
                System.out.println("Federal Income Tax:$" + (6780.00 + (.275 * (income2 - 45200))));
            }
            if ((income2 > 109250.00) && (income2 <= 166500.00)) {
                System.out.println("Federal Income Tax:$" + (24393.75 + (.305 * (income2 - 109250.00))));
            }
            if ((income2 > 166500.00) && (income2 <= 297350.00)) {
                System.out.println("Federal Income Tax:$" + (41855.00 + (.355 * (income2 - 166500.00))));
            }
            if (income2 > 297350.00) {
                System.out.println("Federal Income Tax:$" + (88306.00 + (.391 * (income2 - 297350.00))));
            }
        } else {
            System.out.println("Error. Try again");
        }
    }
}

最佳答案

如果您对C样式的打印感到满意（这是我在这里推荐的建议），则可以使用System.out.printf（），它与C的printf（）非常相似。

System.out.printf ("Federal Income Tax: $%.2f", federalTax);