java - 使用 try catch 执行 while 循环

Question

public static void main(String[] args) throws IOException {

    InputStreamReader isr = new InputStreamReader(System.in);
    BufferedReader br = new BufferedReader(isr);

    boolean format = false;
    int grades = 0;

    do {
        System.out.println("Enter course mark (0-100): ");

        try {
            String input = br.readLine();
            grades = Integer.parseInt(input);

        } catch (NumberFormatException | IOException e) {
            System.out.println("Error number format!");
        }

    } while (!format);

    if (grades > 100 || grades < 100) {
        System.out.println("Please enter within the range (0-100)");
    }

    System.out.println("Your grades is " + grades);

}

我在这里做错了什么，我正在努力实现这个目标

Enter course mark (0-100): qwerty
Bad input data type.
Enter course mark (0-100): -12
Input out of [0, 100] range!
Enter course mark (0-100): 24
Your grades is 24

Answer 1

改变

do {
    try {
        String input = br.readLine();
        grades = Integer.parseInt(input);
    }
    catch(...) { ... }
} while (!format);

至

do {
    try {
        String input = br.readLine();
        grades = Integer.parseInt(input);
        format = true; // Add this line
    }
    catch(...) { ... } 
    if (grades > 100 || grades < 100) {
        System.out.println("Please enter within the range (0-100)");
        format = false;
    }

} while (!format);

如果执行流程达到format = true;，则意味着用户的输入是正确的，并且将确保您打破输入循环。