Close Scanner when entering "0"

Question

I am writting a program where the user enters a String input and the program finds the number of words and the number of int numbers. Scanner should close when the user enters "0".

My code

import java.util.Scanner;

public class RunMe
{
public static void main(String[] args)
{
    Scanner in = new Scanner(System.in);
    String  input = in.nextLine();
    Counter numbers = new Counter();
    Counter words = new Counter();
    Scanner s = new Scanner(input).useDelimiter("\\s");

    while(s.nextInt() != 0)
    {
        if(s.hasNextInt())
        {
            numbers.add();
        }
        else
        {
            words.add();
        }
    }

    s.close();
    in.close();
    System.out.println("Number of numbers : " + numbers.value());
    System.out.println("Number of words : " + words.value());

}
}

and the class Counter

public class Counter
{
    private int value;

    public int add()
    {
        value++;
        return value;
    }
    public int value()
    {
        return value;
    }
}

When I run my program I get the following excepion:

Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Scanner.java:909)
    at java.util.Scanner.next(Scanner.java:1530)
    at java.util.Scanner.nextInt(Scanner.java:2160)
    at java.util.Scanner.nextInt(Scanner.java:2119)
    at RunMe.main(RunMe.java:13)

Can you please include a sample input in your post as well?. — Pavan Dittakavi, Nov 01 '15 at 15:10
s.nextInt() will only read in a number and not a string(word). When you try to enter a word s.nextInt() will give you InputMismatchException because it's expecting a number. — Yan, Nov 01 '15 at 15:12

Yassin Hajaj · Answer 1 · 2015-11-01T15:15:22.740

3

Change the condition of your main loop to check if there is something to read and use a break if the numeral is equals to 0.

Solution

while(s.hasNext())
{
    if(s.hasNextInt())
    {
        if (s.nextInt() == 0) break;
        numbers.add();
    }
    else
    {
        s.next();
        words.add();
    }
}

edited Nov 01 '15 at 15:15

answered Nov 01 '15 at 15:13

Yassin Hajaj

21,337
9
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1

nice way of checking if the input is an int or not! – Yan Nov 01 '15 at 15:15
1

@Yan Thank you. That's nice :) – Yassin Hajaj Nov 01 '15 at 15:17
1

Scanner still doesn't close when entering 0. I have to click "enter" to calculate the number of words and numbers – Konstantina Papagiannopoulou Nov 01 '15 at 15:25
@KonstantinaPapagiannopoulou Do you mean that you don't want an "enter" click (i.e., immediately calculate the number of words and numbers while user press "0")? – Tsung-Ting Kuo Nov 01 '15 at 15:33
1

@Tsung-TingKuo exactly! Is it possible? – Konstantina Papagiannopoulou Nov 01 '15 at 15:36
@KonstantinaPapagiannopoulou I just posted another answer for your reference :-) – Tsung-Ting Kuo Nov 01 '15 at 15:39

score 0 · Accepted Answer · edited May 23 '17 at 12:03

0

With Scanner the console input must be feed using "enter". To avoid this, some other native library would be required, such as JLine. There are other options in this similar question.

edited May 23 '17 at 12:03

Community

1
1

answered Nov 01 '15 at 15:38

Tsung-Ting Kuo

1,171
6
16
21

@KonstantinaPapagiannopoulou Thanks a lot! – Tsung-Ting Kuo Nov 01 '15 at 15:49

Close Scanner when entering "0"

2 Answers2

Solution