java - 验证，如果无效则通知，返回循环

Question

我的这部分代码遇到问题。该程序要求输入一些信息(姓名、ID、年级等)，然后打印结果。

我决定脱离教程，现在已经把头撞到了众所周知的墙上 -

我想要的伪代码:

Ask user for grade between 9 and 12
If input is less than 9 or greater than 12, return failed message and -return to loop-
If input acceptable, continue to next question. 

当前代码如下:

do {
    System.out.print("Grade (9-12): ");
    while (!keyboard.hasNextInt()) {
        System.out.printf("message saying you're wrong");
        keyboard.next();
    }
    userGrade = keyboard.nextInt();
} while (userGrade >= 9 || userGrade <= 12);

Answer 1

尝试这样的事情:

boolean correct = true;
do {
    System.out.print("Grade (9-12): ");
    userGrade = keyboard.nextInt();
    if (userGrade < 9 || userGrade > 12) {
        correct = false;
        System.out.println("message saying you're wrong");
    } else {
        correct = true;
    }
} while (!correct);