Java Scanner if/else 和 while 语句

Question

这个问题已经有答案了:

How to use java.util.Scanner to correctly read user input from System.in and act on it? (1 个回答)

已关闭 8 年前。

我正在尝试制作一个接收用户输入的程序，然后在程序中稍后使用该输入。我遇到的问题是破例。例如，如果我只希望用户输入 0 和他之前输入的数字之间的数字。下面是一个示例:

    Scanner input = new Scanner(System.in); 
    System.out.println("What length do you want your array to be?");
    int length = input.nextInt(); 
    int[] arr = full(length);
    print(arr);
    System.out.println();
    System.out.println("Write a number between (0-"+length+"):");//Its here I want to add an exception.
    int number = input.nextInt();                       //if the user types in a greater value
    check(arr,number);                                  //of "length" or smaller value than 0
                                                        //I want the question to repeat itself
                                                        //until the criteria is met

您不必担心“检查”或“打印方法”。

Answer 1

我不相信你需要一个Exception，只是一个循环。就像一个do-while循环，例如

int number;
do {
    System.out.println("Write a number between (0-" + length + "):");
    number = input.nextInt();
    if (number < 0) {
        System.out.printf("%d is too low%n", number);
    } else if (number > length) {
        System.out.printf("%d is too high%n", number);
    }
} while (number < 0 || number > length);
check(arr, number);