Question

This is a code sample. If I was to enter numerator: 5 and Denominator: 0

I get an exception like this:

Exception in thread "main" java.lang.ArithmeticException: / by zero
at ExceptionHandling.DivideByZeroExceptions.quotient(DivideByZeroExceptions.java:10)
at ExceptionHandling.DivideByZeroExceptions.main(DivideByZeroExceptions.java:22)

I know I have to include ( throws Arithmetic Exception )
But, How would I know that I need to use a inputMismatchException?

 // Try DivideByZeroExceptions

  public class DivideByZeroExceptions {

public static int quotient(int numerator, int denominator) {
    return numerator / denominator;
}

public static void main(String[] args) {

    Scanner input = new Scanner(System.in);

    System.out.println("Please enter an integer numerator: ");
    int numerator = input.nextInt();
    System.out.println("Please enter an integer denominator: ");
    int denominator = input.nextInt();

    int result = quotient(numerator, denominator);
    System.out.printf("\nResult: %d / %d = %d\n", numerator, denominator,
            result);

}

}

Answer 1

Not sure exactly what your asking about inputMismatchException, but this is what you should do:

public static int quotient(int numerator, int denominator) {
    if(denominator == 0)
        throw new IllegalArgumentException("Cannot divide by 0!");
    return numerator / denominator;
}

IllegalArgumentException extends RuntimeException, not just Exception. As such, it will simply stop execution of the thread after it occurs, so it doesn’t need to be caught/thrown (of course you can still catch it outside the method in order to prevent the Thread from stopping).