Question

我有一个正在上学的作业。我几乎已经完成了99％的工作，但是我为最后一件事而苦苦挣扎。

最后一个开关选项需要进行计算，只要使用它的人按下“ 1”键即可。如果没有，它将给出一条消息，提示密钥错误。

我的问题是它可以毫无问题地进行计算，但是即使有人按下“ 1”以外的任何东西，它仍然可以完成计算。

我想念什么？

int option, quantity; 
    float childTotal=0; 
    final double childCost=18.00; 
    float adultTotal=0;
    final double adultCost=36.00;
    float seniorTotal=0;
    final double seniorCost=32.50;

    Scanner input = new Scanner(System.in); //InputStream initialisation


    System.out.println("@@@@@  Welcome to Zoo Victoria  @@@@@");
    System.out.println();
    System.out.println("MAIN MENU");
    System.out.println();
    System.out.println("Please choose from the following ticket type");
    System.out.println();
    System.out.println("1 = Child (4-5 years)");
    System.out.println("2 = Adult (18+ years)");
    System.out.println("3 = Senior (60+ years)");
    System.out.println();
    System.out.println("Enter your ticket type");
    option=input.nextInt();
    System.out.println("Enter the total number of tickets to be purchased");
    quantity=input.nextInt();
    System.out.print("You wish to purchase " +(quantity));
    switch (option) {
        case 1: System.out.println (" child tickets at $18.00");
                break;
        case 2: System.out.println (" adult tickets at $36.00");
                break;
        case 3: System.out.println (" senior tickets at $32.50");
                break;
        }
    System.out.println("Press 1 to confirm purchase");
    option=input.nextInt();
    {
        switch (option) {
        case 1: childTotal=(float) (childTotal + (childCost * quantity));
                System.out.println(childTotal);
                break;
        case 2: adultTotal=(float) (adultTotal + (adultCost * quantity));
                System.out.println(adultTotal);
                break;
        case 3: seniorTotal=(float) (seniorTotal + (seniorCost * quantity));
                System.out.println(seniorTotal);
                break;
        default:
                System.out.println("Incorrect Key");
        }

 }
    }
}

Answer 1

我相信，原因是您对两个不同的操作使用了相同的变量。就像这里：

您重新初始化了选项变量，然后在打算使用第一个选项= input.nextInt（）时再次使用它

option = input.nextInt();

switch (option) {
    case 1:
        childTotal = (float) (childTotal + (childCost * quantity));
        System.out.println(childTotal);
        break;
    case 2:
        adultTotal = (float) (adultTotal + (adultCost * quantity));
        System.out.println(adultTotal);
        break;
    case 3:
        seniorTotal = (float) (seniorTotal + (seniorCost * quantity));
        System.out.println(seniorTotal);
        break;
    default:
        System.out.println("Incorrect Key");
}

可能的解决方案：

System.out.println("Press 1 to confirm purchase");
        if(input.nextInt() == 1){




        switch (option) {
            case 1:
                childTotal = (float) (childTotal + (childCost * quantity));
                System.out.println(childTotal);
                break;
            case 2:
                adultTotal = (float) (adultTotal + (adultCost * quantity));
                System.out.println(adultTotal);
                break;
            case 3:
                seniorTotal = (float) (seniorTotal + (seniorCost * quantity));
                System.out.println(seniorTotal);
                break;
            default:
                System.out.println("Incorrect Key");
        }
        }else{
            System.out.println("err");
            // do what you want
        }

Answer 2

第二个switch语句中的逻辑不正确。考虑这个例子，假设我购买了一张高级票（在您的情况下为3张），并且在确认（按1）后，控制权转到case 1，即为孩子计算账单。因此，我们得到的输出不是$32.50，而不是$18.00。

您可以简单地要求用户使用相同的选项来确认购买：

System.out.println("Please choose from the following to confirm purchase");
System.out.println("1 = Child (4-5 years)\n2 = Adult (18+ years)\n3 = Senior (60+ years)");
option = input.nextInt();
switch (option) {
case 1:
    childTotal = (float) (childTotal + (childCost * quantity));
    System.out.println(childTotal);
    break;
case 2:
    adultTotal = (float) (adultTotal + (adultCost * quantity));
    System.out.println(adultTotal);
    break;
case 3:
    seniorTotal = (float) (seniorTotal + (seniorCost * quantity));
    System.out.println(seniorTotal);
    break;
default:
    System.out.println("Incorrect Key");
}

切换选项和默认

2 个答案: