Java 编写循环/while循环？

我在高中的一个编程课上，我被分配了一个任务，做一个基本的小计和顶级计算器，但我在一家餐馆工作，所以做一个只允许你读一种食物的计算器似乎有点毫无意义。所以我试着让它能够接受多种食物，并将它们添加到一个价格变量中。很抱歉，如果此代码中的某些代码看起来效率低下或冗余。当然，这只是高中

问题是，当我运行它时，它会询问用户是否还想添加其他食物，当我输入“是”或“否”时，程序不会执行任何操作。继续跑，但不走得更远。有什么解释吗

import java.text.NumberFormat;
import java.util.Scanner;

public class Price {

    /**
     * @param args
     */
    public static void main(String[] args) {

        final double taxRate = .0887; //8.87% Tax Rate
        double tipRate;
        int quantity1;
        Scanner kb = new Scanner(System.in);
        double subtotal, tax, tip, totalCost1, unitPrice1 = 0;
        String done;

        System.out.println ("How many of the first item did you get?: ");
        quantity1 = kb.nextInt();

        for (int i = 0; i < quantity1; i++)
        {
        System.out.println ("What was the price of that single item "+(i+1) + ": ");
        unitPrice1 = kb.nextDouble();

        System.out.println ("Was there another food item you'd like to add?: ");
        done=kb.next();
        while (done.equalsIgnoreCase("Yes"));
        }

        System.out.println ("What percent would you like to tip? (Formatted like 0.10 for 10%, 0.20 for 20%, etc.): ");
        tipRate = kb.nextDouble();

        subtotal= quantity1 * unitPrice1;
        tax = subtotal * taxRate;
        totalCost1 = subtotal + tax;
        tip = totalCost1 * tipRate;
        totalCost1 = totalCost1 + tip;


        //Formatting
        NumberFormat money = NumberFormat.getCurrencyInstance();
        NumberFormat tipMoney = NumberFormat.getCurrencyInstance();
        NumberFormat taxPercent = NumberFormat.getPercentInstance();
        NumberFormat tipPercent = NumberFormat.getPercentInstance();


        System.out.println ("Your total before tax is: " + money.format(subtotal));
        System.out.println ("The tax is " + money.format(tax) + " at " + tipPercent.format(taxRate));
        System.out.println ("The tip at " + tipPercent.format(tipRate) + " is " + tipMoney.format(tip));

    }

}

导入java.text.NumberFormat；
导入java.util.Scanner；
公共类价格{
/**
*@param args
*/
公共静态void main（字符串[]args）{
最终双重税率=.0887；//8.87%税率
双蒂普拉特；
int数量1；
扫描仪kb=新扫描仪（System.in）；
双倍小计、税金、小费、总成本1、单价1=0；
字符串完成；
System.out.println（“您得到的第一个项目有多少？：”；
quantity1=kb.nextInt（）；
对于（int i=0；i

这里有一个无限循环：

while (done.equalsIgnoreCase("Yes"));

一旦输入

Yes

，它将一直坐在那里，什么也不做，因为

done

的值是

Yes

，并且永远不会更改

你的循环结构也有点奇怪。您的外部

for

循环的运行次数与第一项的数量相同。但你不应该只把这个数字乘以成本吗？因为您运行循环的时间与用户输入的项目数相同（通过预先询问），或者您不询问他们项目总数，只要让他们输入

Yes

，如果他们想添加更多项目；你不可能两个都做

您的循环可能如下所示：

String input = "Yes";
while(input.equalsIgnoreCase("Yes")) {
    System.out.println ("How many of the first item did you get? ");
    quantity1 = kb.nextInt();

    System.out.println ("What was the price of that single item? ");
    unitPrice1 = kb.nextDouble();

    //total += unitPrice1 * quantity1 - you don't have this in your code, but this is where you would be calculating the running total

    System.out.println("Was there another food item you'd like to add? ");
    input = kb.next();
}

---

这里有一个无限循环：

while (done.equalsIgnoreCase("Yes"));

一旦输入

Yes

，它将一直坐在那里，什么也不做，因为

done

的值是

Yes

，并且永远不会更改

你的循环结构也有点奇怪。您的外部

for

循环的运行次数与第一项的数量相同。但你不应该只把这个数字乘以成本吗？因为您运行循环的时间与用户输入的项目数相同（通过预先询问），或者您不询问他们项目总数，只要让他们输入

Yes

，如果他们想添加更多项目；你不可能两个都做

您的循环可能如下所示：

String input = "Yes";
while(input.equalsIgnoreCase("Yes")) {
    System.out.println ("How many of the first item did you get? ");
    quantity1 = kb.nextInt();

    System.out.println ("What was the price of that single item? ");
    unitPrice1 = kb.nextDouble();

    //total += unitPrice1 * quantity1 - you don't have this in your code, but this is where you would be calculating the running total

    System.out.println("Was there another food item you'd like to add? ");
    input = kb.next();
}

---

这里有一个无限循环：

while (done.equalsIgnoreCase("Yes"));

一旦输入

Yes

，它将一直坐在那里，什么也不做，因为

done

的值是

Yes

，并且永远不会更改

你的循环结构也有点奇怪。您的外部

for

循环的运行次数与第一项的数量相同。但你不应该只把这个数字乘以成本吗？因为您运行循环的时间与用户输入的项目数相同（通过预先询问），或者您不询问他们项目总数，只要让他们输入

Yes

，如果他们想添加更多项目；你不可能两个都做

您的循环可能如下所示：

String input = "Yes";
while(input.equalsIgnoreCase("Yes")) {
    System.out.println ("How many of the first item did you get? ");
    quantity1 = kb.nextInt();

    System.out.println ("What was the price of that single item? ");
    unitPrice1 = kb.nextDouble();

    //total += unitPrice1 * quantity1 - you don't have this in your code, but this is where you would be calculating the running total

    System.out.println("Was there another food item you'd like to add? ");
    input = kb.next();
}

---

这里有一个无限循环：

while (done.equalsIgnoreCase("Yes"));

一旦输入

Yes

，它将一直坐在那里，什么也不做，因为

done

的值是

Yes

，并且永远不会更改

你的循环结构也有点奇怪。您的外部

for

循环的运行次数与第一项的数量相同。但你不应该只把这个数字乘以成本吗？因为您运行循环的时间与用户输入的项目数相同（通过预先询问），或者您不询问他们项目总数，只要让他们输入

Yes

，如果他们想添加更多项目；你不可能两个都做

您的循环可能如下所示：

String input = "Yes";
while(input.equalsIgnoreCase("Yes")) {
    System.out.println ("How many of the first item did you get? ");
    quantity1 = kb.nextInt();

    System.out.println ("What was the price of that single item? ");
    unitPrice1 = kb.nextDouble();

    //total += unitPrice1 * quantity1 - you don't have this in your code, but this is where you would be calculating the running total

    System.out.println("Was there another food item you'd like to add? ");
    input = kb.next();
}

---

当用户输入yes时，您需要退出for循环，所以您可以在此处使用标签，如下所示：

  outerloop:
  for (int i = 0; i < quantity1; i++)
            {
            System.out.println ("What was the price of that single item "+(i+1) + ": ");
            unitPrice1 = kb.nextDouble();

            System.out.println ("Was there another food item you'd like to add?: ");
            done=kb.next();
            while (done.equalsIgnoreCase("Yes")){
                     break outerloop;
               }
            }

outerloop:
对于（int i=0；i

您当前的代码在while中不起任何作用