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BOOK: Beginning Java 2
This is the forum to discuss the Wrox book Beginning Java 2, SDK 1.4 Edition by Ivor Horton; ISBN: 9780764543654
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Old November 26th, 2003, 03:09 PM
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Default Problem with Chapter 2, Exercise 2

Hi,

I would be very grateful if someone could shed some light on this simple problem.

Basically I am trying to do Exercise 2 in Chapter 2 of Ivor Horton's Begining Java 2 SDK 1.4 Edition.

The exercise asks that you take a double like 1234.5678. Put the integral part of the double into a long i.e. 1234. This part is OK. Then the exercise asks that you put the fraction into a short i.e. 5678.

This last part is where I am having problems. Other than hard-coding a fix is there a neater way of doing this. Is there a function available already that does this trick?

I am only begining with Java so any help at all would be gratefully received.

Regards,
Paul.
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Old November 26th, 2003, 06:09 PM
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Here's Ivor's solution:

public class DisplayParts
{
  public static void main(String[] args)
  {
    // Initialize a double variable to some value (1234.5678)
    double myNumber = 1234.5678;
    long integPart = 0;
    short fracPart = 0;
    int decPlaces = 4;

    // Find the integer part
    integPart = (int)myNumber;
    // Find the number of Decimal places
    fracPart = (short)Math.round((myNumber - integPart)*Math.pow(10,decPlaces));

    System.out.println("myNumber is " + integPart + "." + fracPart);

    // What happens if decPlaces > 4? How could this be rectified?
  }
}


I hope this helps

Martyn
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Old November 29th, 2003, 01:22 PM
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> int decPlaces = 4;
> fracPart = (short)Math.round((myNumber - integPart)*Math.pow(10,decPlaces));

Fancy solution, Ivor, congratulations!

My Question:

In the BigDecimal class we have a variable called "scale", that sets the number of digits.
Is there a similar field or method available in the encapsulating Double class?
(Excuse me my jargon practise)



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Old December 1st, 2003, 05:13 AM
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No, there isn't a scale() method in Double.

Cheers

Martyn
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