数组索引超出范围异常4 [重复]答案

【问题标题】：Array index out of bounds exception 4 [duplicate]数组索引超出范围异常4 [重复]
【发布时间】：2016-06-15 16:31:35
【问题描述】：

我在尝试删除或显示我创建的用户时不断收到错误消息。指向实际删除或显示某个用户的代码行。我似乎无法弄清楚错误来自哪里。

import java.util.*;
public class contactInfo {
    public static void main(String[] args) {
        String tracker[][] = {
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",},
                {" ", " ", " ", " ",}
        };

        Scanner input = new Scanner(System.in);
        int picker = 0;

        while (true) {
            System.out.print("Please choose an option: \n 1. Add a user  \n 2. Delete a user  \n 3. Display a user  \n 4. Quit ");
            picker = input.nextInt();
            if (picker == 1) {
                addUser(tracker);
            } else if (picker == 2) {
                deleteUser(tracker);
            } else if (picker == 3) {
                displayUser(tracker);
            } else {
                break;
            }
        }
    }

    public static String[][] addUser(String[][] add) {
        Scanner input = new Scanner(System.in);

        System.out.print("Which user is this information for (1 - 10): ");
        int user = input.nextInt();
        System.out.println(" ");

        System.out.print("Enter the users first name: ");
        add[user][0] = input.next();
        System.out.println(" ");

        System.out.print("Enter the users last name: ");
        add[user][1] = input.next();
        System.out.println(" ");

        System.out.print("Enter the users phone number (without dashes): ");
        add[user][2] = input.next();
        System.out.println(" ");

        System.out.print("Enter the users age: ");
        add[user][3] = input.next();
        System.out.println(" ");

        return add;
    }

    public static String[][] deleteUser(String[][] del) {
        Scanner input = new Scanner(System.in);

        System.out.print("Which user would you like to delete?: ");
        int user = input.nextInt();

        for (int i = 0; i < del.length - 1; i++) {
            del[user][i] = " ";
        }

        return del;
    }

    public static String[][] displayUser(String[][] displ) {
        Scanner input = new Scanner(System.in);

        System.out.print("Which user would you like to display?: ");
        int user = input.nextInt();

        for (int i = 0; i < displ.length; i++) {
            System.out.print(displ[user][i] + " ");
        }

        return displ;
    }
}

【问题讨论】：

您的用户正在输入您的“用户”变量，您要求一个值 1-10 并将其用作数组的索引。数组在 Java 中是从零开始索引的。因此，要么从用户输入中减去 1，要么请求 0-9。此外，您应该检查收到的索引是否
顺便说一句，在删除和显示 for 循环中，不要使用 displ.length，而是使用 displ[user].length，因为这是您在循环内访问的内容！！！那是你的例外。但是请看我之前的评论，因为您还有其他错误。
感谢您的信息！我的课程中还没有涉及 ArrayList 类，但我会自己做一些研究。

标签： java arrays indexoutofboundsexception

【解决方案1】：

您的跟踪器是一个二维数组。 10 行，每行 4 个字符串。问题是这段代码：

    for (int i = 0; i < del.length - 1; i++)
    {
        del[user][i] = " ";
    }

您遍历 4 个字符串的数组，但变量 i 将从 0 变为 8。您想要的是这样的：

    for (int i = 0; i < del[user].length; i++)
    {
        del[user][i] = " ";
    }

【讨论】：

非常感谢，成功了！
您能否将我的回答标记为已接受？
抱歉，第一次使用本站=P。标记！
将从 0 变为 9。
不，条件是"i

【解决方案2】：

请使用 displ[user].length 或 del[user].length，而不是使用 displ.length 或 del.length 作为限制。

【讨论】：