java - 我在创建基本联系人管理器时遇到问题。

Question

这段代码我遇到了一些问题。我做的第一件事显然是创建了一些数组，这些数组将保存每个联系人的所有信息，因为我正在构建一个基本的联系人管理器。我的主要方法只是调用我的菜单方法来启动序列。在我的菜单中，用户可以选择他们想做什么。他们选择哪个选项将取决于他们在键盘上输入的数字。反过来，这将激活不同的方法。

我遇到的问题如下:

1. 按“1”(查看所有联系人)后，计算机会吐出 100 个空值或 100 次重复我上次在“2”中输入的任何内容，添加联系人。

2. 虽然是的，我确实希望我的菜单在某个操作发生后自动重复，但它会立即执行。例如，在我按下“1”后所有重复发生后，它会直接返回主菜单，并且很难以这种方式阅读所有内容。

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import java.io.IOException;
import java.util.Scanner;


``public class MainHub {

// global variables that will be needed
static String[] name = new String[100];
static String[] number = new String[100];
static String[] email = new String[100];
static String[] address = new String[100];
static String[] birthday = new String[100];
static String[] nickname = new String[100];
static int x;
public static int counter = 0;
static Scanner in = new Scanner(System.in);


public static void main (String[] args) throws IOException{

    menu(); // call menu method to start program

}

//Holds all the information for the menu
public static void menu() throws IOException{
    int choice = -1; //start at -1 as to not compete with an index number


    while (choice != 7){ //while loop to get a choice from user

        //telling the user what everything is, simple output message
        System.out.println("\t Main Menu\n");
        System.out.println("Enter the corrosponding number for what you want to do.\n");
        System.out.println("1.View all contacts\n2.Add contact\n3.Edit contact\n4.Delete contact\n5.Save contact list\n6.Load contact list\n7.Exit");

        choice = Integer.valueOf(in.nextLine()).intValue(); //this allows the user input to be read and used to make a choice

        switch(choice){
            case 1: viewAllContacts(); //if user inputs 1, call method to view all the contacts
                    break; //stop the loop
            case 2: addContact(); //if user inputs 2, call method to add a contact
                    break; //stop the loop
            case 3: editContact(); // if user inputs 3, call method to view contacts and choose one to edit
                    break; //stop the loop
            case 4: deleteContact(); // if user inputs 4, call method to view contacts and choose one to delete
                    break; //stop the loop
            case 5: saveContact(); // if user inputs 5, call method to save current contact list into a text file
                    break; //stop the loop
            case 6: loadContact(); // if user inputs 6, call method to load a text file to input contacts into array
                    break; //stop the loop
            case 7: System.out.println("You are exiting"); // if user inputs 7, tell user he is leaving
                    break; //stops the loop
                default: System.out.println("That is not one of the options."); // if user doesn't input one of above numbers, it will tell user not an option
        }
    }
}


//holds information, once called upon the user will be able to see all their contacts
public static void viewAllContacts(){


    while(counter<100){ //while the counter has less than 101 it will print out the full list of contacts

        if(counter>0){ //if counter is greater than 0 print list of contacts

    System.out.println("Full name: " +name[x]);
    System.out.println("Number: " +number[x]);
    System.out.println("E-mail Address: " +email[x]);
    System.out.println("Home Address: " +address[x]);
    System.out.println("Birthday: " +birthday[x]);
    System.out.println("Nickname: " +nickname[x]);
    System.out.println(" "); //space so that way the contact list is a bit prettier 

    counter++;

    }else{
        System.out.println("There are no contacts in your list yet."); //else tell user there is no contacts
    }
}

}

//lets the user add a contact and all the information
public static void addContact() throws IOException{

    //as long as the counter is less than 101 you can add contacts



    if(counter<100){



        System.out.println("Enter Contact's Full Name: "); //allows user to add a name to contact
        name[x] = in.nextLine(); //whatever is typed will be added into name variable

        System.out.println("Enter Contact's Number: "); //allows user to add a number to contact
        number[x] = in.nextLine(); //whatever is typed will be added into number variable

        System.out.println("Enter Contact's E-mail Address: "); //allows user to add an E-mail address to contact
        email[x] = in.nextLine(); //whatever is typed will be added into email variable

        System.out.println("Enter Contact's Home Address: "); //allows user to add a home address to contact 
        address[x] = in.nextLine(); //whatever is typed will be added into address variable

        System.out.println("Enter Contact's Birthday: "); //allows user to add a birthday to contact
        birthday[x] = in.nextLine(); //whatever is typed will be added into birthday variable

        System.out.println("Enter Contact's Nickname: "); //allows user to add a nickname to contact
        nickname[x] = in.nextLine(); //whatever is typed will be added into nickname variable

        counter++; //adds 1 to counter to allow space for next contact in arrays


    }else{
        System.out.println("Sorry, the contact list is full."); //if counter is 101 it will print the contact list is full
    }

    System.out.println("Your contact has been added");
}

Answer 1

问题是您使用 x 作为数组的索引，但是 x 永远不会递增。

当你递增counter

尝试

System.out.println("Full name: " +name[counter]);

与添加联系人

一样

整理你的索引。