Question

我的任务是创建一个包含名字，姓氏，电话号码和年龄的多维数组程序。我目前收到错误：

线程“main”中的异常java.lang.Error：未解决的编译问题：输入无法解决

at Lab2.<init>(Lab2.java:19)
at Lab2.main(Lab2.java:7)

** Editx2，我想我已经明白了。我理想的是想用名字和姓氏删除联系人，但我无法理解。我尝试添加一个新的sysout提示输入姓氏，就像我为名字做的那样，然后添加另一个if语句，但它最终做了一些时髦的事情。

import java.util.Scanner;

public class Lab2 {
    static String[][] contacts = new String[10][4];

    public static void main (String [] args) {
        new Lab2();
    }

    public Lab2() {
        String[][] contacts = new String[10][4];
        Scanner input = new Scanner(System.in);
        System.out.println("Welcome to my Contacts Directory.  Enter a selection below: ");

        while(true) {
            System.out.println("1: Add a contact");
            System.out.println("2: Remove a contact");
            System.out.println("3: Display your contacts");
            System.out.println("0: Exit the Contacts Directory");

            int userChoice = input.nextInt();

            switch(userChoice) {
        case 1:         
            addContacts(contacts);
            break;

        case 2:
            removeContacts(contacts);
            break;

        case 3:
            displayContacts(contacts);
            break;

        case 0:
            System.out.println("You are leaving the directory! Goodbye!");
            System.exit(0);
            }
        }
    }

    private static void addContacts(String[][] contacts) {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter First Name");
        String fName = input.nextLine();

        System.out.println("Enter Last Name");
        String lName = input.nextLine();

        System.out.println("Enter Phone Number");
        String num = input.nextLine();

        System.out.println("Enter Age");
        String age = input.nextLine();

            for (int i = 0; i < 10; i++) {
                if (contacts[i][0] == null || contacts[i][0].equals(null)) {
                    contacts[i][0] = fName;
                    contacts[i][1] = lName;
                    contacts[i][2] = num;
                    contacts[i][3] = age;
                    boolean Inserted = true;
                    break;


            }
        }
    }

    private static void removeContacts(String[][] contacts) {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter the first name of the contact you want to remove: ");
        String removeContact = input.nextLine();
        if (removeContact != null) {
            for (int i = 0; i < contacts.length; i++) {
                for (int j = 0; j < contacts[i].length; j++) {
                    if (removeContact.equals(contacts[i][j])) {
                        contacts[i][0] = null;
                        contacts[i][1] = null;
                        contacts[i][2] = null;
                        contacts[i][3] = null;
                        break;
                    }
                }
            }
        }
        }


    private static void displayContacts(String[][] contacts) {
        for(int i = 0; i < contacts.length; i++) {
            for(int j = 0; j < contacts[i].length; j++) {
                System.out.println(contacts[i][j] + " ");
            }
            System.out.println();
        }
    }
}

Answer 1

您的＆＃34;输入＆＃34;变量[object]不是全局变量，它是另一个函数中的范围变量。

添加，删除和显示方法

1 个答案: