Question

我目前正在尝试完成此程序，但是当我测试我的switch语句时，它直接进入我的默认情况并说我输入的信息无效。

我的任务

我必须从用户那里收到一个月并将其发送到我的案例陈述，以便为特定案件执行我的代码。您可能会注意到，每个案例中都有一个密钥，此密钥用于个人目的。请不要理会。

我的问题

case语句直接进入我的default语句，该语句向用户发出无效的信息消息。

我的进步

这将是我的完整程序，除了我的case语句将每个月识别为无效输入外，一切似乎都正常工作

// Import Libraries
    import javax.swing.*;
    import java.util.*;
    import java.io.*;


// This is my program.
public class DateCalc

{
public static void main (String[] args)
{
    String month;
    String day;
    String inputYear;
            Scanner  keyboard = new Scanner(System.in); 

                // receiving input for my age variable
                System.out.print( "Please Enter The Month Of The Date :");
                month = keyboard.nextLine();
                // receiving input for my weight variable
                System.out.print( "Please Enter The Day Of The Date : ");
                day = keyboard.nextLine();
                // receiving input for my height variable
                System.out.print( "Please Enter The Year OF The Date : ");
                inputYear = keyboard.nextLine();
                String stringYear = ""+ inputYear.charAt(inputYear.length()-2) + inputYear.charAt(inputYear.length()-1);
                int year = Integer.parseInt(stringYear);
                int intDay = Integer.parseInt(day);

        switch(month) 
        {  

          // I tried to test my program by using my first case " January ", However it goes right through every case directly for my default case.  

            case "January || january" :
            int janKey = 1;
            int janQuarter = year / 4;
            int janSum = year + janQuarter + intDay + janKey;

            System.out.print( " Date Entered Was : " + month + ","+ day + "" + inputYear);
            System.out.print( " Last Two Digits Of The Year Were : " + year);
            System.out.print( " One Quarter Of Last Two Digits : " + janQuarter);
            System.out.print( " The Given Day Of The Month Entered : " + day);
            System.out.print( " The Index Key This Moth is : " + janKey);
            System.out.print( " The Sum Of All The number Above is : " + janSum);
            System.out.print( " \n \n The Day Of The Week Was : ");
            int weekDay = dayLookUp(janSum);
            System.out.print( " \n \n The Day Of The Week Was : " + weekDay);
            break;


            case "February || february":  
            int febKey = 4;
            break;  


            case "March || march":  
            int marKey = 4;
            break;


            case "April || april":  
            int aprKey = 0; 
            break;

            case "May || may":  
            int maykey = 2; 
            break;

            case "June || june":  
            int junKey = 5; 
            break;

            case "July || july":  
            int julKey = 0; 
            break;

            case "August || august":  
            int augKey = 3; 
            break;

            case "September || september":  
            int septKey = 6; 
            break;

            case "October || october":  
            int octKey = 1; 
            break;

            case "November || november":  
            int novKey = 4; 
            break;

            case "December || december":  
            int decKey = 4; 
            break;

            //  IN MY DEFUALT CASE " inputValidation " WILL BE EXECUTED
            default:
            JOptionPane.showMessageDialog(null," Invalid Entry Please Try Again " );

        }
}

public static int dayLookUp ( int janSum )
{
    int sum = janSum;
    int day = 14 % 7;
    return day;

}
}

Answer 1

现在你正在这样做，它正在寻找整个字符串，从字面上看，不是将||解释为任何形式的or。

您可以将开关中的元素设置为大写或小写：

switch(month.toLowerCase()) {
    case "january" :
        ...
        break;
    case "february":
        ...
    ...
}

或者你必须加倍案例元素：

switch (month) {
    case "January":
    case "january":
       ...
       break;
    case "February":
    case "february":
        ...
    ...
}

Answer 2

错误发生在"January || january"这是一个String使用case "January": case "january":

Answer 3

您无法以这种方式测试替代品，case "January || january":无效。您可以使用多个case s

提供替代方案

switch (month) {
case "january":
case "January":
    int janKey = 1;

没有干预break。当输入january时，这会导致第二种情况下降。当然，其他几个月也一样。

我的Switch语句没有按预期工作

3 个答案: