如果没有输入数据，如何实现取消语句

Question

我仍在学习编程，确实需要一些帮助，我需要制作一个具有很多功能的程序并且大部分都已完成，但我在创建特定行时遇到困难。我正在使用 while 循环让用户输入数字来计算最大、最小以及随机生成的数字的总和。我需要编写一种方法，如果用户在输入任何其他数据之前输入退出语句 -99，它会说 "You have entered no numbers." 并退出程序。任何帮助都会很棒，下面是我的程序代码。

public class LargestSmallest
{
  public static void main(String [] args)
  {
    //identifier declarations
    int number;
    int numberend = -99;
    int largest = Integer.MIN_VALUE;
    int smallest = Integer.MAX_VALUE;
    int number1;
    int sum1;
    int sum2;

    //create a Scanner object to read from the keyboard & input 
    Scanner input = new Scanner(System.in);

    //create a random object
    Random randomNumbers = new Random();

    //get one random number
    number1 = randomNumbers.nextInt(9); 

    //display prompts and get input
    System.out.println("Enter an integer, or -99 to quit:");

    //loop for number input
    while ((number = input.nextInt()) != numberend) {
        System.out.println("Enter an integer, or -99 to quit:");

        //largest & smallest number sorting

        if (number > largest) {
          largest = number;
        }
        if (number < smallest) {
          smallest = number;
        }
    }
    //calculate final sums
    sum1 = number1 + largest;
    sum2 = number1 + smallest;

    //final statements
    System.out.println("Largest:" + largest);
    System.out.println("Smallest:" + smallest);
    System.out.println("Random:" + number1);
    System.out.println("Largest + Random:" + sum1);
    System.out.println("Smallest + Random:" + sum2);
  }
}

Answer 1

如果您只是想在没有用户输入的情况下以适当的消息结束程序，您可以这样做：

while ((number = input.nextInt()) != numberend) {
    System.out.println("Enter an integer, or -99 to quit:");

    //largest & smallest number sorting

    if (number > largest) {
    largest = number;
    }
    if (number < smallest) {
    smallest = number;
    }
}
if (largest > Integer.MIN_VALUE) {
    //calculate final sums
    sum1 = number1 + largest;
    sum2 = number1 + smallest;

    //final statements
    System.out.println("Largest:" + largest);
    System.out.println("Smallest:" + smallest);
    System.out.println("Random:" + number1);
    System.out.println("Largest + Random:" + sum1);
    System.out.println("Smallest + Random:" + sum2);
} else {
    System.out.println("You have entered no numbers");
}

如果您想忽略 -99 并留在循环中：

while ((number = input.nextInt()) != numberend || largest == Integer.MIN_VALUE) {
    while (number == numberend) {
        System.out.println("You have entered no numbers, you can't quit");
        number = input.nextInt();
    }
    System.out.println("Enter an integer, or -99 to quit:");

    //largest & smallest number sorting

    if (number > largest) {
    largest = number;
    }
    if (number < smallest) {
    smallest = number;
    }
}

如果没有输入数据，如何实现取消语句

How to implement a cancel statement if no data entered

java

if-statement

exit