java循環中斷與if語句？

Question

在嘗試做一些練習來學習Java時，我編寫了一個簡單的程序來計算工作時間計數並提供應得的薪水。

package horulycalc;

import java.util.Arrays;
import java.util.Scanner;

public class HorulyCalc {

    public static void main(String[] args) {
        Scanner param = new Scanner(System.in);
        String [] titles  = {"Developer","Designer","Data Entry","Manager","CEO"};
        System.out.println("Hello and welcome to Job Counter");
        System.out.println("Please enter you Job Title");
        String title = param.nextLine();
        while(!Arrays.asList(titles).contains(title)){
            System.out.println("Please enter valid Job Title"); 
            title = param.nextLine();
            if(Arrays.asList(titles).contains(title)){
                System.out.println("Please enter your Hours for this week :");
                String count = param.nextLine();
                System.out.printf("Your Salary is : $ %f",HoursMath(HourRate(title),Integer.parseInt(count)));
                break ;
            }
        }
    }

    public static int HourRate(String jobTitle){
        int rate = 0;
        switch(jobTitle){
            case "Developer":
                rate = 10 ;
                break;
            case "Designer":
                rate = 8 ;
                break ;
            case "Data Entry":
                rate = 6;
                break ;
            case "Manager":
                rate = 15 ;
                break;
            case "CEO":
                rate = 36;
                break ;
        }
        return rate ;
    }

    public static float HoursMath(int rate ,int count){
        float total ;
        total = rate * count ;
        return total ;
    }
}

如果我是第一次添加錯誤的職位，則程序運行正常，我的意思是輸入不包含在職位數組中。

當我第一次輸入有效的職位名稱（例如“ CEO”）時，程序中斷，netbeans完成時如何

Answer 1

這是因為當用戶首次輸入有效值（在您的數組中）時，您沒有執行任何操作。

    System.out.println("Please enter you Job Title");
    String title = param.nextLine(); // read title..
    while(!Arrays.asList(titles).contains(title)){ // while title is not present in array.
     }
 // nothing here--> what if title is present in the array / list?
  //So,Put this code here :. The below lines of code will be executed only hen you have a valid entry.
    System.out.println("Please enter your Hours for this week :");
    String count = param.nextLine();
    System.out.printf("Your Salary is : $ %f",HoursMath(HourRate(title),Integer.parseInt(count)));
            break 

Answer 2

由於您的while循環已經在測試有效的標題，因此您也不應在循環內對其進行測試。

這比較簡單：

while(!Arrays.asList(titles).contains(title)){
    System.out.println("Please enter valid Job Title"); 
    title = param.nextLine();
}
System.out.println("Please enter your Hours for this week :");
String count = param.nextLine();
System.out.printf("Your Salary is : $ %f",HoursMath(HourRate(title),Integer.parseInt(count)));

您不必以這種方式擺脫循環。 一旦退出循環，就知道您擁有有效的標題。