Question

您好我是初学者，今天我开始学习数组。我写了以下工作程序。

import java.util.Scanner;

    public class Arr {
        public static void main(String[] args) {
            Scanner scanner = new Scanner(System.in);
            System.out.println("enter some numbers");
            int[] x = new int[5];
            x[0] = scanner.nextInt();
            x[1] = scanner.nextInt();
            x[2] = scanner.nextInt();
            x[3] = scanner.nextInt();
            x[4] = scanner.nextInt();
            String string = "the numbers as requested are : ";
            for(int i = 0; i < x.length; i++) {
                System.out.println(string + x[i]);
            }
            scanner.close();
        }
    }

然而，如果我的阵列有1000个数字，这个过程就会变得很烦人。是否有一种简单的方法可以在不输入input scanner for each package

的情况下输入数字

Answer 1

不要只是硬编码。使用while循环并使用限制。

public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("enter some numbers");
        int[] x = new int[5];
        int j = 0;
        while (scanner.hasNext() && j < limit) { 
            if (scanner.hasNextInt()) {
                x[j] = scanner.nextInt();
                j++;
            }

        }

        String string = "the numbers as requested are : ";
        for (int i = 0; i < x.length; i++) {
            System.out.println(string + x[i]);

        }
        scanner.close();

    }

4输入的限制为5，99输入的限制为100。

Answer 2

然而，如果我的阵列有1000个数字，这个过程就会变得很烦人。是否有一种简单的方法来输入数字而无需为每个包输入输入扫描器

是的，通过使用循环。使用 for-loop 或 while循环。

int[] array = new int[5];
for(int x=0; x<array.length; x++) //Prompt as many times as the array size
    array[x] = scanner.nextInt();

一般情况下，当您确定要迭代的次数时，使用 for循环，当您不确定循环次数时，使用 while循环运行

Answer 3

扩展@Suresh-Atta提及的没有硬编码限制的想法我会考虑使用ArrayList，请参阅Why is it preferred to use Lists instead of Arrays in Java来存储动态数量的项目。这样做意味着您需要一些指示符来退出输入上的读数，在这种情况下，单词“exit”

import java.util.Scanner;
import java.util.ArrayList;

public class Arr {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("enter some numbers");
        ArrayList<Integer> numbers = new ArrayList<Integer>();

        while (scanner.hasNext()) {        
            if (scanner.hasNextInt()) {
                numbers.add(scanner.nextInt());
            } else {
                String s1 = scanner.next();
                if ("exit".equalsIgnoreCase(s1)) {
                     break;
                }
            }
        }

        String string = "the numbers as requested are : ";
        for (Integer x : numbers) {
            System.out.println(x);
        }
        scanner.close();

     }
 }

Answer 4

Here's a sample:

public static void main(String[] args) {
    int ARRAY_LENGTH = 5;
    int[] intArray = new int[ARRAY_LENGTH];
    int x = 0;

    try (Scanner reader = new Scanner(System.in)) {
        System.out.println("Enter " + ARRAY_LENGTH + " numbers [Something else exits]: ");
        while (x < ARRAY_LENGTH) {
            if (reader.hasNextInt()) {
                intArray[x++] = reader.nextInt();
            } else {
                System.out.println("Input not a number, exiting.");
                break;
            }
        }
    }

    //Print array
    System.out.print("Array has: ");
    for (int number : intArray) {
        System.out.print(number + " ");
    }
    System.out.println();
}

Here's another:

public static void main(String[] args) {
    ArrayList<Integer> array = new ArrayList();
    try (Scanner reader = new Scanner(System.in)) {
        System.out.println("Enter numbers [Something else exits]: ");
        while (reader.hasNextInt()) {
            array.add(reader.nextInt());
        }
    }

    //Print array
    System.out.print("Array has: ");
    for (int number : array) {
        System.out.print(number + " ");
    }
    System.out.println();
}

使用scanner将数据输入数组

4 个答案: