Java Char Empty Character Detection

Question

Right so im using java on eclipse and kept coming up with a problem. What im trying to fix is when the user is promoted to press any key. When the key is enter and no Char the program collapses due to it can't find a character.

my code is:

Scanner scan = new Scanner(System.in);
    Game game = new Game();
    char quit=' ';

    while (quit != 'N') 
    {
        game.play();

        System.out.println("Play again? Press any key to continue, or 'N' to quit");
        quit = scan.nextLine().toUpperCase().charAt(0);

    }

When ever enter is pressed, it stops the program due to no characters inputted. Is there a way around this and let the program continue when enter is pressed?

couettos · Accepted Answer · 2015-06-09 13:27:39Z

2

I would write it like this :

    Scanner scan = new Scanner(System.in);
    String line;

    do{
        game.play();
        System.out.println("Play again? Press any key to continue, or 'N' to quit");
        line = scan.nextLine();

    }while (line.isEmpty() || line.toUpperCase().charAt(0) != 'N');

answered Jun 9, 2015 at 13:27

couettos

5915 silver badges15 bronze badges

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

Comments

brso05 · Accepted Answer · 2015-06-09 13:31:12Z

1

You can check the length:

while (quit != 'N') 
{
    game.play();

    System.out.println("Play again? Press any key to continue, or 'N' to quit");
    String test = scan.nextLine().toUpperCase();
    if(test != null && test.length() > 0)
    {
       quit = test.toUpperCase().charAt(0);
    }
    else
    {
         //handle your else here
         quit = ' '; //this will keep it from terminating
    }
}

Store the next line in a string then check to make sure it is not null and its length is at least 1. If so then get the first char. If not then decide how you want to handle that situation.

edited Jun 9, 2015 at 13:31

answered Jun 9, 2015 at 13:18

brso05

13.3k2 gold badges25 silver badges41 bronze badges

3 Comments

Steven Sharman Over a year ago

Ok thanks @brso05 ive added that just trying to stop program terminating now :D

brso05 Over a year ago

@StevenSharman you can set quit = ' ' in your else if you don't want it to terminate...

Steven Sharman Over a year ago

@brso05 Ok thanks, I also found couettos to work as well but I will recommend both

Kartic · Accepted Answer · 2015-06-09 13:31:03Z

0

Instead of quit = scan.nextLine().toUpperCase().charAt(0);, we can write:

String str = scan.nextLine().toUpperCase();
quit = ((str == null || "".equals(str)) ? ' ' : str.charAt(0));

answered Jun 9, 2015 at 13:31

Kartic

2,9835 gold badges26 silver badges43 bronze badges

Collectives™ on Stack Overflow

Java Char Empty Character Detection

3 Answers 3

Comments

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related