Java 如何使用循环允许用户选择多个项目？

我正在设置一个商店菜单，我希望用户能够使用循环选择另一个项目。我想问你还需要什么吗？在用户选择了一个项目之后，这个过程将继续，直到用户说不。我还没有弄清楚如何在使用循环时做到这一点

    System.out.println("\nHere are our products:");
    System.out.println("\t[L]arge Toothpick ---- $10.25");
    System.out.println("\t[M]edium Toothpick --- $ 5.25");
    System.out.println("\t[S]mall Toothpick ----   Free");

    final double cLTP = 10.25; // large toothpick
    final double cMTP = 5.25; // medium toothpick
    final double cSTP = 1.25; // small toothpick
    int QNTY; // quantity
    double TCOST; // total cost without tax
    double FCOST; // final cost with tax

    String response;
    char FL; // first letter
    System.out.println("\nWhat would you like to buy?");
    response = keyboard.nextLine();
    FL = response.charAt(0);

    if(FL == 'L' || FL == 'l')
    {
        System.out.println("How many?");
        QNTY = keyboard.nextInt();
        TCOST = QNTY * cLTP;
    }
    else if (FL == 'M' || FL == 'm')
    {
        System.out.println("How many?");
        QNTY = keyboard.nextInt();
        TCOST = QNTY * cMTP;
    }
    else if (FL == 'S' || FL == 's')
    {
        System.out.println("How many?");
        QNTY = keyboard.nextInt();
        TCOST = QNTY * cSTP;
    }           
}

感谢大卫·华莱士和评论家们对我的帮助。我已经弄明白了，代码如下：

if(FL == 'L' || FL == 'l')
    {
        System.out.println("How many?");
        QNTY = keyboard.nextInt();
        keyboard.nextLine();
        TCOST = QNTY * cLTP;

        System.out.println("Would you like to buy anything else?");
        response = keyboard.nextLine();
        FL = response.charAt(0);

        if(FL == 'N' || FL == 'n')
        {
            System.out.println("Okay then, your subtotal is: $"+TCOST);
            System.out.println("What is your sales tax? (Format: 5%, Enter: .05)");
            TAX = keyboard.nextDouble();
            FCOST = TCOST + TCOST * TAX;
            System.out.printf("Your total is: $%.2f\n", FCOST);
        }
        else
        {
            do
            {
                System.out.println("What would you like to buy?");  
                response = keyboard.nextLine();
                FL = response.charAt(0);

                if(FL == 'L' || FL == 'l')
                {
                    System.out.println("How many?");
                    QNTY = keyboard.nextInt();
                    keyboard.nextLine();
                    TCOST = TCOST + QNTY * cLTP;
                }
                if(FL == 'M' || FL == 'm')
                {
                    System.out.println("How many?");
                    QNTY = keyboard.nextInt();
                    keyboard.nextLine();
                    TCOST = TCOST + QNTY * cMTP;
                }
                if(FL == 'S' || FL == 's')
                {
                    System.out.println("How many?");
                    QNTY = keyboard.nextInt();
                    keyboard.nextLine();
                    TCOST = TCOST + QNTY * cSTP;
                }
                System.out.println("Would you like to buy anything else?");
                response = keyboard.nextLine();
                FL = response.charAt(0);
            }while(FL == 'y' || FL == 'Y');

            System.out.println("Okay then, your subtotal is: "+TCOST);
            System.out.println("What is your sales tax? (Format: 5%, Enter: .05)");
            TAX = keyboard.nextDouble();
            FCOST = TCOST + TCOST * TAX;
            System.out.printf("Your total is: $%.2f\n", FCOST);
        } 
    }  

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您想要的循环类型是do while循环。插入

do {

在要重复的零件的开头

最后，执行从用户处获得答案所需的处理，并将要检查的条件放在一段时间内，如下所示

} while (condition);

---

如果条件涉及一些您将要检查的变量，我相信它会，那么您应该在do之前声明它们，这样它们就不会超出范围。

您想要的循环类型是do while循环。插入

do {

在要重复的零件的开头

最后，执行从用户处获得答案所需的处理，并将要检查的条件放在一段时间内，如下所示

} while (condition);

---

如果条件涉及一些您将要检查的变量，并且我确信它会，那么您应该在do之前声明它们，这样它们就不会超出范围。

do while循环在这种情况下会有所帮助。Good luckdo{/*您想在循环中做什么，将答案存储为一个名为wantMore*/}的布尔值，而wantMore==truedo while循环在这种情况下会有所帮助。Good luckdo{/*您想在循环中做什么，在wantMore==true时，将您还想做什么的答案存储为一个名为wantMore*/}的布尔值