如何将用户输入存储在整数数组中？ [英] How can I store user inputs in an array of integers?

问题描述

我不知道用户将输入多少个数字，我需要程序在数组到达行尾时停止在数组中插入数字，因为在新行中，用户将输入一个与此无关的数字。

举例：

用户可以输入：

1 5 7 8 9 5

4

或：

%5%4%8%9%4%2%1%3%2%4

7

我需要的数组是，例如1：[1，5，7，8，9，5]

推荐答案

如果您的需求允许您询问用户，您可以这样做：

import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        int[] num;
        Scanner scanner=new Scanner(System.in);
        System.out.print("How many integers you want to enter: ");
        int n = 0;
        if(scanner.hasNextInt()) {
            n=scanner.nextInt();
        }
        num=new int[n];
        for(int i=0;i<n;i++) {
            System.out.printf("Enter integer %d: ",i+1);
            if(scanner.hasNextInt()) {
                num[i]=scanner.nextInt();
            }           
        }
        System.out.println(Arrays.toString(num));
    }
}

示例运行：

How many integers you want to enter: 3
Enter integer 1: 10
Enter integer 2: 15
Enter integer 3: 20
[10, 15, 20]

您也可以按如下方式操作：

import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        int[] num;
        Scanner scanner = new Scanner(System.in);
        System.out.print("How many integers you want to enter: ");
        int n = 0;
        if (scanner.hasNextInt()) {
            n = scanner.nextInt();
            scanner.nextLine();
        }
        num = new int[n];
        System.out.print("Enter the integers separated by a space: ");
        String[] strNums = null;
        if (scanner.hasNextLine()) {
            strNums = scanner.nextLine().split(" ");
        }
        if (strNums != null) {
            for (int i = 0; i < n; i++) {
                try {
                    num[i] = Integer.parseInt(strNums[i]);
                } catch (Exception e) {
                    System.out.println("Invalid input");
                    break;
                }
            }
            System.out.println(Arrays.toString(num));
        }
    }
}

示例运行：

How many integers you want to enter: 3
Enter the integers separated by a space: 10 15 20    
[10, 15, 20]

但是，如果您希望整数数量不受限制，则应该使用List而不是数组(因为数组的大小在初始化时是固定的)，如下所示：

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        List <Integer> intList=new ArrayList<Integer>();
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter the integers separated by a space: ");
        String[] strNums = null;
        if (scanner.hasNextLine()) {
            strNums = scanner.nextLine().split(" ");
        }
        if (strNums != null) {
            for (String strNum: strNums) {
                try {
                    intList.add(Integer.parseInt(strNum.trim()));
                } catch (Exception e) {
                    System.out.println("Invalid input");
                    break;
                }
            }
            System.out.println(intList);

            //You can even get an array out of the list as follows:
            Integer[] nums = intList.toArray(new Integer[0]);
            System.out.println(Arrays.toString(nums));
        }
    }
}

示例运行：

Enter the integers separated by a space: 10 20 30 40
[10, 20, 30, 40]
[10, 20, 30, 40]

祝您一切顺利！

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