java 中的循环开关盒

Question

我目前正在研究将提示学生级别类型的代码（切换大小写），并确定每种类型的学生将收到的现金数额。 然后我想总结每个学生级别收到的所有现金。 我是一个初学者，只学了几个星期的 java，非常感谢任何建议。 这是我所做的，也有注释。

System.out.print("Level code :");
levelCode = input.next().charAt(0);

do {

    switch (levelCode) {
        case 'F':
            System.out.print("Total Foundation student = ");
            studentFoundation = input.nextInt();
            foundationCash = studentFoundation * 50;
            break;
        case 'D':
            System.out.print("Total Diploma student = ");
            studentDiploma = input.nextInt();
            diplomaCash = studentDiploma * 50;
            break;
        case 'B':
            System.out.print("Total Bachelor student = ");
            studentBachelor = input.nextInt();
            bachelorCash = studentBachelor * 70;
            break;
        case 'M':
            System.out.print("Total Master student = ");
            studentMaster = input.nextInt();
            masterCash = studentMaster * 90;
            break;
        case 'P':
            System.out.println("Total PhD student = ");
            studentPhd = input.nextInt();
            phdCash = studentPhd * 90;
            break;
        default:
            System.out.println("Invalid code");
            break;

    }
} while (levelCode < 5); //i dont know what to put here in order to loop the switch case

totalCash = foundationCash + diplomaCash + bachelorCash + masterCash + phdCash; //here i want to calculate all the input entered

System.out.println("Total cash amount = " + totalCash);

Answer 1

假设您只希望在执行default情况时返回到 go 的循环，您可以通过不同的方式进行。

使用 label

LOOP: for (;;) { // forever loop
    System.out.print("Level code :");
    levelCode = input.next().charAt(0);

    switch (levelCode) {
        case 'F':
            // code here
            break LOOP; // <=== break out of the loop, not the switch statement
        case 'D':
            // code here
            break LOOP; // <=== break out of the loop, not the switch statement
        ...
        default:
            // code here
    }
}

使用 boolean

boolean error;
do {
    System.out.print("Level code :");
    levelCode = input.next().charAt(0);

    error = false;
    switch (levelCode) {
        case 'F':
            // code here
            break;
        case 'D':
            // code here
            break;
        ...
        default:
            error = true;
            // code here
    }
} while (error);

使用特殊值，例如 null

String levelCode;
do {
    System.out.print("Level code :");
    levelCode = input.next();

    switch (levelCode) {
        case "F":
            // code here
            break;
        case "D":
            // code here
            break;
        ...
        default:
            // code here
            levelCode = null;
    }
} while (levelCode == null);

Answer 2

我认为一个简单的解决方案是首先提示用户键入有多少学生，然后将您的 switch 语句放入 for 循环中。

Answer 3

所以我尝试使用 for 循环方法，感谢 Andreas 举了一个例子:)，它成功了！

现在我不知道如何提示用户再次输入代码以继续循环，但我输入了几行来提示代码并且它按预期工作，但我确定这不是最有效的方法吗？

我打算在用户输入最后一个输入/输入无效代码后打破循环

这是新修改的代码

循环：对于（；；）{

    switch(levelCode){
     case 'F' : System.out.print("Total Foundation student = ");
                studentFoundation = input.nextInt();
                foundationCash = studentFoundation * 50;
                
                System.out.print("Level code :");//here im trying to prompt the user to enter another code to continue the loop
    levelCode = input.next().charAt(0);
    break;
     case 'D' : System.out.print("Total Diploma student = ");
                studentDiploma = input.nextInt();
                diplomaCash = studentDiploma * 50;
                
                System.out.print("Level code :");
    levelCode = input.next().charAt(0);
    break;
     case 'B' : System.out.print("Total Bachelor student = ");
                studentBachelor = input.nextInt();
                bachelorCash = studentBachelor * 70;
                
                System.out.print("Level code :");
    levelCode = input.next().charAt(0);
    break;
     case 'M' : System.out.print("Total Master student = ");
                studentMaster = input.nextInt();
                masterCash = studentMaster * 90;
                
                System.out.print("Level code :");
    levelCode = input.next().charAt(0);
    break;
     case 'P' : System.out.println("Total PhD student = ");
                studentPhd = input.nextInt();
                phdCash = studentPhd * 90;
                break LOOP;
                
      default : System.out.println("Invalid code :");
                break LOOP;
                
               
    }      
  }