java - 重复用户输入，同时将其添加到数组列表

Question

我试图询问用户是否想将另一个人添加到数组列表“list”中。我的想法是循环询问，然后将这些输入添加到数组“inf”中，然后将该数组放入数组列表中。现在，当我重复代码时，它只会删除以前的输入；我该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

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

 //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"));

希望这对您有帮助。请尝试一下并告诉我。