java arraylist that stores userinput

问题

how can I get it to go back to start another directory when the user types yes and also how do I print the arraylist out using a print format

thanks

import java.util.ArrayList;
import java.util.Scanner;

public class AAA
{
    public static void main(String[] args) 
{

    ArrayList<String> name = new ArrayList<String>();
    ArrayList<Integer> phone = new ArrayList<Integer>(); 
    Scanner scanner = new Scanner(System.in); 


    {
        System.out.println("Please enter your name: ");
        name.add(scanner.next());
        System.out.println("Please enter your number: ");
        phone.add(scanner.nextInt());

        System.out.println("Do you want to add a directory yes/no?");
        String answer = scanner.nextLine(); 

        if (answer.equals("yes"));
        //want it to go back to start another direcotry here

        else 
    {

        System.out.println("Thanks for adding to the directory");
        System.out.println(answer());
    }


    }

    }
}

回答1:

Try to use a while true, and then, when the user types no, you break the look. The code seems like this:

ArrayList<String> name = new ArrayList<String>();
ArrayList<Integer> phone = new ArrayList<Integer>(); 
Scanner scanner = new Scanner(System.in); 

while(true){
    System.out.println("Please enter your name: ");
    name.add(scanner.next());
    System.out.println("Please enter your number: ");
    phone.add(scanner.nextInt());

    System.out.println("Do you want to add a directory yes/no?");
    String answer = scanner.next(); 

    if (answer.equals("no")){
        System.out.println("Thanks for adding to the directory");
        System.out.println(answer());
        break; //
    }

}

There are another strategies, like using a do/while. But essentially you have to use a loop.

回答2:

You can easily print out an ArrayList:

System.out.println(list);

It will print something like:

[one, two, three]

where one, two, three are the results of invocation of toString() or array list's elements.

You can remove [] easily by:

System.out.println(list.toString().replace("[", "").replace("]", ""));

You you need to use your custom format implement print in loop:

for (String s : list) {
    System.out.println(format(s));
}

回答3:

import java.util.ArrayList;
import java.util.Scanner;

public class AAA {

    public static void main(String[] args) {

        ArrayList<String> name = new ArrayList<String>();
        ArrayList<Integer> phone = new ArrayList<Integer>();

        Scanner scanner = new Scanner(System.in);
        String answer = "";

        {
            do {
                System.out.println("Please enter your name: ");
                name.add(scanner.next());
                System.out.println("Please enter your number: ");
                phone.add(scanner.nextInt());
                System.out.println("Do you want to add a directory yes/no?");
                answer = scanner.next();
            } while (answer.equals("yes"));
            if (answer.equals("yes")); //want it to go back to start another direcotry here
            else {

                System.out.println("Thanks for adding to the directory");
                for (int i = 0; i < name.size(); i++) {
                    System.out.print(name.get(i)+"\t");
                    System.out.print(phone.get(i));
                    System.out.println("");
                }
            }


        }

    }
}

来源：https://stackoverflow.com/questions/4460788/java-arraylist-that-stores-userinput