我有两个类来计算ISP计划的成本和收集输入/显示成本。 ISPMain.java和ISP.java ISPMain应该显示服务计划,并要求用户通过软件包字母(如软件包a,软件包b或软件包c)选择他们的计划。我已经设置好了,所以用户输入角色来选择计划。如果计划不是套餐c(无限计划),则提示用户输入他们使用的小时数。

输入小时数并将其存储在hoursUsed中后,ISP.java将计算成本,然后ISPMain.java将其显示出来。我的问题是我的ISP中的switch语句仅显示默认值,我不确定为什么。谁能解释?

public class ISPMain
{

    public static void main(String[] args)
    {
        char pkg;
        double hoursUsed;

        Scanner kb = new Scanner(System.in);

        System.out.println("The three packages offered are: ");
        System.out.println("Package A: For $9.95 per month, 10 hours of access are provided. \nAdditional hours are $2.00 per hour.");
        System.out.println("Package B: For $14.95 per month, 20 hours of access are provided. \nAdditional hours are $1.00 per hour.");
        System.out.println("Package C: For $19.95 per month, unlimited access is provided.");

        System.out.println("Please type the letter of the package you have: ");
        pkg = kb.nextLine().toUpperCase().charAt(0);

        if(pkg == 'A')
        {
            System.out.print("Enter number of hours: ");
            hoursUsed = kb.nextDouble();
        }
        else if(pkg == 'B')
        {
            System.out.print("Enter number of hours: ");
            hoursUsed = kb.nextDouble();
        }
        else if(pkg == 'C')
        {
            System.out.print("You have unlimited access! No need to enter hours used. \n");
        }


        ISP user = new ISP();
        System.out.print("Total charges: " + user.calculateCharges());

    }
}


ISP.java的switch语句:

public double calculateCharges()
{

    switch (pkg)
    {
        case 'A':
        if (hoursUsed < 10)
        {
            return 9.95;
        }

        else
        {
            return (hoursUsed - 10)*2 + 9.95;
        }

        case 'B':
        if (hoursUsed < 20)
        {
            return 14.95;
        }

        else
        {
            return (hoursUsed - 20) + 14.95;
        }

        case 'C':
            return 19.95;

        default:
            System.out.println("Invalid input!");
            return 0;
    }


}


总结一下,我的if else是否可以正常工作,但开关仅显示“无效输入”

最佳答案

正如其他人所说,您需要将pkg变量放入switch语句的范围内。尝试这个:

public double calculateCharges(char pkg){
 switch(pkg){
     case('A'):{
      //insert code here
       break;
     }
     case('B'):{
    //insert code here
     break;
     }
     case('C'):{
     //insert more code here
     break;
     }
  default:{
  //code here
  break;
  }
 }
}


然后像这样调用您的方法:

System.out.print("Total charges: " + user.calculateCharges(pkg));

10-08 12:03