[Java]

[punx]

Hello once again. I am trying to round a double to the nearest Integer, and display the answer in a DoubleField for a GUI application. I've tried to cast the variable being used to type int, and tried using the Format.justify method. Here's the code, any help would be appriciated. Thanks.

/**
*Calculates the population growth
**/

import javax.swing.*;
import BreezySwing.*;
import BreezySwing.Format;
public class PopulationGrowth extends GBFrame
{
	private JLabel initialOrganismsLabel;
	private JLabel growthRateLabel;
	private JLabel hoursLabel;
	private JLabel growthHoursLabel;
	private DoubleField initialOrganismsField;
	private DoubleField growthRateField;
	private DoubleField hoursField;
	private DoubleField growthHoursField;
	private DoubleField totalOrganismsField;
	private JButton calculateButton;
   
//*************************Constructor Method***********************************
   public PopulationGrowth()
   {
   	initialOrganismsLabel = addLabel  ("Initial Organisms" ,1,1,1,1);
   	initialOrganismsField = addDoubleField 	(0.0 ,1,2,1,1);
   	growthRateLabel = addLabel  ("Growth Rate" ,2,1,1,1);
   	growthRateField = addDoubleField  (0.0 ,2,2,1,1);
   	hoursLabel = addLabel ("Hours to achieve this rate" ,3,1,1,1);
   	hoursField = addDoubleField	(0.0 ,3,2,1,1);
   	growthHoursLabel 	= addLabel  ("Hours to grow" ,4,1,1,1);
   	growthHoursField 	= addDoubleField 	(0.0 ,4,2,1,1);
   	totalOrganismsField = addDoubleField 	(0 ,5,1,2,2);
   	calculateButton = addButton ("Calculate Population" ,6,2,1,1);
   }
//******************************************************************************

   public void buttonClicked (JButton buttonObj)
   {
   		double 	initialOrganisms,
   	  			growthRate,
   	  			hours,
   	  			growthHours,
   	  			growPeriod,
   	  			totalOrganisms = 0;
   	  			
   		if (buttonObj == calculateButton)
	  	{
	  		initialOrganisms= initialOrganismsField.getNumber();
	  		growthRate = growthRateField.getNumber();
	  		hours = hoursField.getNumber();
	  		growthHours = growthHoursField.getNumber();
	  		growPeriod = hours / growthHours;
	  		totalOrganisms = (int)initialOrganisms * Math.pow(growthRate,growPeriod);
	 		double temp = Format.justify('l' ,totalOrganisms, 25, 0);
	  		totalOrganismsField.setNumber(temp);
	  	}
   }
   				
	public static void main (String[] args)
   	{
      PopulationGrowth GUI = new PopulationGrowth();							//Instantiate the GUI window
      GUI.setSize (500, 400);													//Set the size of the program
      GUI.setVisible (true);													//Shows the program
   	}
}

[squirellplaying]

Have you tried adding .5 then converting to an Int?

totalOrganisms = (int)((initialOrganisms * Math.pow(growthRate,growPeriod))+.05);

This method will do the math first, then round. Since converting to an Int from a double just cuts off everything after the decimal, adding .5 will "round up" correctly.

[TheShaner]

Requires the import of java.lang.Math:

http://java.sun.com/j2se/1.4.2/docs/...#round(double)

Squirrel's implementation will work too, except you should cast it as a long instead of an int, because depending on how big your number gets, you may end up truncating the value big time.

-Shane

[punx]

Thanks guys, that helped out alot.