Java: ArrayLists w/ Scanner: First element not printing

Question

I was trying to make a program that prints out user-inputted values in an ArrayList, and for the most part, it works. Except it does not print the first element. Here is the code:

import java.util.Scanner;
import java.util.ArrayList;
public class Family {
    public static void main(String[] args){
        ArrayList<String> names=new ArrayList<String>();
        Scanner in=new Scanner(System.in);
        System.out.println("Enter the names of your immediate family members and enter \"done\" when you are finished.");
        String x=in.nextLine();
        while(!(x.equalsIgnoreCase("done"))){
            x = in.nextLine();
            names.add(x);

        }
        int location = names.indexOf("done");
        names.remove(location);
        System.out.println(names);
    }
}

For example if, I enter jack, bob, sally, it'll print [bob, sally]

FYI, you don't need the 2-step indexOf() and remove(). names.remove("done") will do the trick. — shmosel
– shmosel, Commented Mar 2, 2017 at 20:21

Mureinik · Accepted Answer · 2017-03-02 20:17:28Z

4

You're calling nextLine() immediately when you enter the loop, losing the previously inputted line in the process. You should use it before reading an additional value:

while (!(x.equalsIgnoreCase("done"))) {
    names.add(x);
    x = in.nextLine();            
}

EDIT:
This, of course, means that "done" won't be added to names, so the following lines, and they should be removed:

int location = names.indexOf("done");
names.remove(location);

edited Mar 2, 2017 at 20:17

answered Mar 2, 2017 at 20:08

Mureinik

316k54 gold badges400 silver badges405 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

shmosel Over a year ago

@EduardoDennis Sure it does.

Eddie Martinez Over a year ago

@shmosel it gives arrayIndexOutofBounds I just tried it. look at the line where he is doing names.remove the index will be higher than the size of the array list.

Mureinik Over a year ago

@EduardoDennis those lines should, of course, be removed - I've edited it into my answer.

Eddie Martinez Over a year ago

of course ¯_(ツ)_/¯ you and @shmosel should upvote my question because I was right :D

Eddie Martinez Over a year ago

@shmosel it wasnt working, there I removed it ahah lets become allies since we are always in the Java questions :) I even gave upvote

|

shmosel · Accepted Answer · 2017-03-02 20:22:37Z

1

String x=in.nextLine();

this line outside the while loop consumes first input because as you enter the while loop, you again call x=in.nextLine(); without saving the first input, so it gets lost. Hence it doesn't gets printed because its not in the ArrayList.

Just remove String x=in.nextLine(); that is included before the while loop and your code will work fine.

String x="";

System.out.println("Enter the names of your immediate family members and enter \"done\" " +
"when you are finished.");

while(!(x.equalsIgnoreCase("done"))){
    x = in.nextLine();
    names.add(x);
}

edited Mar 2, 2017 at 20:22

shmosel

51k7 gold badges81 silver badges147 bronze badges

answered Mar 2, 2017 at 20:07

Yousaf

29.5k6 gold badges54 silver badges78 bronze badges

Comments

Eddie Martinez · Accepted Answer · 2017-03-02 20:05:53Z

0

because the first element is consumed by the first x= in.nextLine(); and you never added it to the list.

Try this:

 System.out.println("Enter the names of your immediate family members and enter \"done\" when you are finished.");
        String x="";
        while(!(x.equalsIgnoreCase("done"))){
            x = in.nextLine();
            names.add(x);

        }

answered Mar 2, 2017 at 20:05

Eddie Martinez

13.9k15 gold badges86 silver badges109 bronze badges

Collectives™ on Stack Overflow

Java: ArrayLists w/ Scanner: First element not printing

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related