在Java中不爆发循环

Question

我已经用Java编写了这个开关案例程序。但是，while循环没有中断。代码如下：

import java.util.Scanner;
public class exam001 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int marks;
        while(true) {
            System.out.println("This is a gade checker program");
            System.out.println("Enter the marks from 0 to 100: ");
            System.out.println("Enter the marks: ");
            marks = scanner.nextInt();
            int grade = marks / 10;
            if (marks > 100) {
                System.out.println("Please enter the marks between the limit assigned");
            }
            else {
                switch(grade) {
                case 10:
                case 9:
                    System.out.println("Your grade is A");
                    break;
                case 8:
                case 7:
                    System.out.println("Your grade is B");
                    break;
                case 6:
                    System.out.println("Your grade is C");
                    break;
                case 5:
                case 4:
                    System.out.println("Your grade is D");
                    break;
                    
                default:
                    System.out.println("Your grade is E");
                    break;
                }
            }
        }
    }
}

我不知道，为什么break函数在这个循环中不起作用…请帮帮我..

Answer 1

使用标签从while中中断而不是开关:

loop:
while(true) {
    // ...
    // later:
    switch (..) {
        case ..:
            break loop;
    } 
}

有关详细信息，请参阅本教程：https://docs.oracle.com/javase/tutorial/java/nutsandbolts/branch.html