java.util.inputMismatchException Dont know why

Question

I'm trying to write a small program to calculate certain grades, but I'm getting an inputMismatchException, but I don't know why. The problem is that I get the exception before I even had the chance to enter an integer.

Could somebody help me out.

    public static void main(String[] args) 
    {
        Scanner input = new Scanner("System.in");

        int passes = 0;
        int failures = 0;
        int studentCounter = 1;
        int result;

        while(studentCounter <= 10)
        {
            //Zelf aangepast = output gewijzigd
            System.out.println("Geef het resultaat in (1 = geslaagd, 2 = gebuisd).");
            result = input.nextInt();

            if(result == 1)
            {
                passes = passes + 1;
            }
            else
            {
                failures = failures + 1;
            }

            studentCounter = studentCounter + 1;
        }

        //Zelf aangepast = output gewijzigd
        System.out.printf("Aantal leerlingen geslaagd: %d\nAantal leerlingen gebuisd: %d\n", passes, failures);

        if(passes > 8)
        {
            //Zelf aangepast = output gewijzigd
            System.out.println("Bonus voor de leerkracht!");
        }
    }
}

So as you can see I can't assign any number to the variable result.

Welcome to SO. Your question is incomplete because it is missing some crucial information: What is the declaration (i.e. type) of result? What input did you provide that caused the exception to be thrown? — Jim Garrison
– Jim Garrison, Commented Jun 21, 2013 at 23:33

zw324 · Accepted Answer · 2013-06-21 23:32:17Z

1

The inputMismatchException means that the Scanner (input) received something not of int which is expected from nextInt:

Thrown by a Scanner to indicate that the token retrieved does not match the pattern for the expected type, or that the token is out of range for the expected type.

So in short, the next token you give the scanner is not an int.

answered Jun 21, 2013 at 23:32

zw324

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Comments

Jurgen Camilleri · Accepted Answer · 2013-06-21 23:35:54Z

0

This happens when the user does not enter a valid integer when calling Scanner.nextInt(). To solve this you could use exceptions like so:

while(studentCounter <= 10)
{
    //Zelf aangepast = output gewijzigd
    System.out.println("Geef het resultaat in (1 = geslaagd, 2 = gebuisd).");
    try {
        result = input.nextInt();
    }
    catch(InputMismatchException i) {
        System.out.println("Please enter integers only.");
        result = 0;
    }

    if(result == 1)
    {
        passes = passes + 1;
    }
    else
    {
        failures = failures + 1;
    }

    studentCounter = studentCounter + 1;
}

answered Jun 21, 2013 at 23:35

Jurgen Camilleri

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