java - 货币格式 - 我如何使用它？

Question

我是一名高中三年级学生。很难弄清楚如何使用货币格式。我正在《Java 编程指南》(第二版)中做一个练习，其中我必须提示员工汉堡、薯条和苏打水的数量。

薯条 1.09 美元，汉堡 1.69 美元，苏打水 0.99 美元。

这是我的代码:

import java.util.Scanner;
/**
 * Order pg. 101
 * 
 * Garret Mantz
 * 2/10/2016
 */
public class Order {

public static void main(String[]args) {

final double pburgers=1.69;
final double pfries=1.09;
final double psodas=0.99;
final double ptax=0.065;
double burgers;
double fries;
double sodas;
double totaltax;
double total;
double tax;
double tendered;
double change;

Scanner input = new Scanner(System.in);


System.out.print("Enter the amount of burgers: ");
burgers = input.nextDouble();
System.out.print("Enter the amount of fries: ");
fries = input.nextDouble();
System.out.print("Enter the amount of sodas: ");
sodas = input.nextDouble();
System.out.print("Enter the amount tendered: ");
tendered = input.nextDouble();



totaltax = (burgers*pburgers)+(fries*pfries)+(sodas*psodas);
tax = totaltax*ptax;
total = totaltax + tax;
change = tendered - total;


System.out.println("Your total before tax is: \n" + totaltax);
System.out.println("Tax: \n" +  tax);
System.out.println("Your final total is: \n" + total);
System.out.println("Your change is: \n" + change);
 }
}

我只想使用货币格式，但我不知道如何使用。我确信这是一个愚蠢的问题，但感谢您的帮助!

Answer 1

将 println 更改为这些，看看是否有帮助:

System.out.format("Your total before tax is: $%-5.2f\n", totaltax);
System.out.format("Tax: $%-5.2f\n", tax);
System.out.format("Your final total is: $%-5.2f\n", total);
System.out.format("Your change is: $%-5.2f\n", change);

还有这个:

NumberFormat formatter = NumberFormat.getCurrencyInstance();
String totalTaxString = formatter.format(totaltax);
String taxString = formatter.format(tax);
String totalString = formatter.format(total);
String changeString = formatter.format(change);

System.out.format("Your total before tax is: %s\n", totalTaxString);
System.out.format("Tax: %s\n", taxString);
System.out.format("Your final total is: %s\n", totalString);
System.out.format("Your change is: %s\n", changeString);

输出:

Your total before tax is: $8.53 
Tax: $0.55 
Your final total is: $9.08 
Your change is: $10.92