Question

我的代码运行正常。但是，当我从名称或年龄输入中输入-1时，输出似乎不正确。如何删除空值和“-1”并显示现有数组？

import java.util.Scanner;

public class quizLoop {
    private static Scanner key = new Scanner(System.in);
    private static Scanner keyNum = new Scanner(System.in);

    public final static int arrayLoop = 5;
    public static String[] nameList = new String[arrayLoop];
    public static int[] age = new int[arrayLoop];

    public static void main(String[] args) {
        System.out.println("NAME & AGE SYSTEM\n-----------------\n");
        for(int i=0; i<arrayLoop; i++) {
            System.out.print("Name: ");
            nameList[i] = key.nextLine();
            if(nameList[i].equals("-1"))
                break;

            System.out.print("Age: ");
            age[i] = keyNum.nextInt();
            if(age[i] < 0)
                break;
        }

        System.out.println("----------");
        for(int i=0; i<nameList.length; i++) {
            System.out.println(nameList[i] + " " + age[i]);
        }
    }
}

Answer 1

目前，当您输入-1时，循环退出。也就是说，只要输入-1，循环就不会再次运行。这是因为您使用break语句。

如果您想让-1允许用户再次启动当前条目，您需要做两件事：

if (nameList[i].equals("-1")) {
    // Take the loop variable down one.
    i--;
    // Instead of break, continue to the next iteration.
    continue;
}

如果您想保持循环的方式，但只想打印非null值，请修改您的打印代码：

for(int i=0; i<nameList.length; i++) {
    if (nameList[i] == null || nameList[i].equals("-1") || age[i] < 0) {
        // Invalid; go to the next one.
        continue;
    } else { // (not strictly necessary)
        System.out.println(nameList[i] + " " + age[i]);
    }
}

Answer 2

尝试使用List而不是Array，如下所示：

import java.util.Scanner;

public class quizLoop {
private static Scanner key = new Scanner(System.in);
private static Scanner keyNum = new Scanner(System.in);

public final static int arrayLoop = 5;
public static List<String> nameList = new ArrayList<String>();
public static List<Integer> ages = new ArrayList<Integer>();

public static void main(String[] args) {
    System.out.println("NAME & AGE SYSTEM\n-----------------\n");

    while (true){
        System.out.print("Name: ");
        String name = key.nextLine();
        if(name.equals("-1"))
            break;

        System.out.print("Age: ");
        Integer age = keyNum.nextInt();
        if(age < 0)
            break;
        nameList.add(name);
        ages.add(age);
    }

    System.out.println("----------");
    for(int i=0; i<nameList.length; i++) {
        System.out.println(nameList[i] + " " + age[i]);
    }
}
}

如何从两个数组中删除/不显示空值？

2 个答案: