Java 柠檬水计算器

Question

分配给:

• 在输出屏幕顶部显示任何欢迎消息

• 创建变量来保存一杯柠檬水的价格值。

• 显示每杯的价格。

• 询问用户的姓名，并将其存储为 String 对象。尽可能称呼用户的姓名。

• 询问用户想要订购多少杯柠檬水。将其保存为具有适当数据类型的变量。

• 将圣地亚哥 8% 的税率存储为程序中的常量变量。

• 计算小计、税金总额和总价，并将其显示在屏幕上。

• 询问用户如何支付柠檬水费用，并将输入保存为 char 变量。

• 要求用户输入“m”(代表金钱)、“c”(信用卡)或“g”(代表金币)

• 使用 DecimalFormat 类，使打印到屏幕上的所有货币数据显示 2 位小数，并显示“$”符号。

需要帮助弄清楚如何在我的程序中将 8% 的税率作为常量变量 这样我就可以计算小计、总税和总价，并将其显示在屏幕上

到目前为止，这就是我所拥有的:

import java.util.Scanner;
import javax.swing.JOptionPane;
import java.text.DecimalFormat;

public class FirstProgram {

    public static void main(String[] args) {
        double cost = 7.55;
        double amount = 7.55;
        final double CA_SALES_TAX = 0.08; 
        int tax, subtotal, total;
        subtotal = (int) (amount * cost);
        tax = (int) (subtotal * CA_SALES_TAX);
        total = tax + subtotal;

        Scanner input = new Scanner(System.in);
        double fnum = 7.55, tax1 = fnum * 0.08, answer = tax1 + fnum; 
        System.out.println("Welcome to the best Lemonade you'll ever taste! ");

        System.out.println("My lemonade would only cost you a measly: $" + amount);

        System.out.println("What is your name?");

        String first_name;
        first_name = input.nextLine();

        System.out.println("Hi " +first_name+ ", how many glasses of lemonade would you like?");
        fnum = input.nextDouble();
        System.out.println("Subtotal: $" + (amount * fnum));

        System.out.println("Tax:    $" + (tax1 * CA_SALES_TAX));
        tax1 = input.nextDouble();

感谢任何帮助

Answer 1

您似乎已经将销售税设置为常量，这就是“final”关键字的用途。至于你的代码，我看到一些冗余，并且不确定你为什么要转换为整数。我根据我认为你想要它做的事情做了一些修改。

public static void main(String[] args) {
    double cost = 7.55;
    final double CA_SALES_TAX = 0.08;
    double subtotal,tax,total;

    Scanner input = new Scanner(System.in);
    System.out.println("Welcome to the best Lemonade you'll ever taste! ");
    System.out.println("My lemonade would only cost you a measly: $" + cost);

    System.out.println("What is your name?");
    String first_name = input.nextLine();

    System.out.println("Hi " +first_name+ ", how many glasses of lemonade would you like?");
    int fnum = input.nextInt();

    //calc subtotal, tax, total 
    subtotal = fnum * cost;
    tax = subtotal *CA_SALES_TAX; 
    total = tax + subtotal;

    // print them all out 
    System.out.println("Subtotal: $" + (subtotal));
    System.out.println("Tax: $" + (tax));
    System.out.println("Total Price: $" + (total));
}