Question

我正在尝试询问用户是否要将其他人添加到数组列表中，＆＃34; list＆＃34;。我的想法是循环询问，然后将这些输入添加到数组中，＆＃34; inf＆＃34;然后将该数组放在数组列表中。现在，当我重复代码时，它只是删除了以前的输入;我将如何制作它，以便在每次迭代后添加到数组列表中？

public class test {

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

        Scanner scan = new Scanner(System.in);

        String ask = "no";

        do {
            System.out.println("Add? (yes/no)");
            ask = scan.nextLine();
            if (ask.equals("yes")){

                //gather user info
                System.out.println("Last Name: ");
                String LastN = scan.nextLine();


                System.out.println("First Name: ");
                String FirstN = scan.nextLine();


                System.out.println("# of Children:");
                String Children = scan.nextLine();


                System.out.println("Address:");
                String Adr = scan.nextLine();

                System.out.println("Phone #:");
                String Pho = scan.nextLine();

                Date dategather = new Date();   
                String Date = String.format("%tD", dategather);

                //Input the data into an array
                String[] inf = {LastN,FirstN,Children,Adr,Date,Pho};

                ArrayList<String> list = new ArrayList<String>();

                Collections.addAll(list,inf);

                System.out.println(list);               

            }

            } while (ask.equals("yes"));

        }
    }

Answer 1

您可以创建一个Person类，其中包含每个人的所有详细信息，并将它们添加到ArrayList中。像这样的东西：（提示：你可以将#children作为整数而不是String）

public class test
{
    public static void main(String[] args) throws FileNotFoundException {
        ArrayList<Person> list = new ArrayList<Person>();

        do
        {
            System.out.println("Add? (yes/no)");
            ask = scan.nextLine();
            if (ask.equals("yes")){
                   System.out.println("Last Name: ");
                    String lastName= scan.nextLine();


                    System.out.println("First Name: ");
                    String firstName= scan.nextLine();


                    System.out.println("# of Children:");
                    String children = scan.nextLine();


                    System.out.println("Address:");
                    String address= scan.nextLine();

                    System.out.println("Phone #:");
                    String phone= scan.nextLine();

                    Date dategather = new Date();   
                    String date = String.format("%tD", dategather);
                    list.add(new Person(lastName, firstName, children,address, phone,date));


            }
        }while (ask.equals("yes"));
    }

}

public class Person
{
    String lastName, firstName, children,address, phone,date
    public Person(String lastName,String firsName,String children,String address,String phone, String date)
    {
        this.lastName=lastName;
        this.firsName=firsName;
        this.children=children;
        this.address=address;
        this.phone=phone;
        this.date=date;
    }
}

在每个循环的代码中，每次重新初始化时，arrayList都会重置。

Answer 2

您希望在do-while结构之外声明列表，如果您想打印每个行条目，那么您可以在do-while结构的末尾执行此操作：< / p>

 //here you declare the list OUTSIDE:

 ArrayList<String> list = new ArrayList<String>();

  do {
            System.out.println("Add? (yes/no)");
            ask = scan.nextLine();
            if (ask.equals("yes")){

                //gather user info
                System.out.println("Last Name: ");
                String LastN = scan.nextLine();

                System.out.println("First Name: ");
                String FirstN = scan.nextLine();

                System.out.println("# of Children:");
                String Children = scan.nextLine();

                System.out.println("Address:");
                String Adr = scan.nextLine();

                System.out.println("Phone #:");
                String Pho = scan.nextLine();

                Date dategather = new Date();   
                String Date = String.format("%tD", dategather);

                //Input the data into an array
                String[] inf = {LastN,FirstN,Children,Adr,Date,Pho};

                Collections.addAll(list,inf);
                //so here you want to display what the person just entered:
                System.out.println("You Have Entered : \n Last Name: "+LastN+"  First Name: "+FirstN+" Children : "+Children+" Address: "+Adr+" Date of Birth: "+Date+" Phone Number: "+Pho);               

            }

            } while (ask.equals("yes"));

我希望这会对你有所帮助。请试一试，让我知道。

将数据列表添加到数组列表时重复用户输入

2 个答案: