Question

When printing out the user input as indvidual words within a line I get a printout of all the words in that line.

System.out.println(userInput.next());

However, when I add the indvidual words to an ArrayList I appear to be getting random words back:

 al.add(userInput.next());

Could someone explain to me what’s going on?

Thanks.

This is a full copy of the code:

import java.util.*;


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

        Scanner userInput = new Scanner(System.in);
        ArrayList<String> al = new ArrayList<String>();


        while(userInput.hasNext()){
            al.add(userInput.next());
            System.out.println(userInput.next());
        }


    }
}

Answer 1

Because next() consumes the next token from the scanner. Thus, when you have:

        al.add(userInput.next());
        System.out.println(userInput.next());

You are actually consuming two tokens from the scanner. The first is being added to the ArrayList and the other is being printed to System.out. A possible solution is to store the token in a local variable, and then add it to the array and print it:

    while (userInput.hasNext()) {
        String token = userInput.next();
        al.add(token);
        System.out.println(token);
    }