Hi everybody, I need some help with my first Java program. My teacher don't teach really good ... I have a problem to solve in my script. At that time all are okay but all number must be rounding to 2 decimal :S

That's all my Java program (He is in french but if you need some explain ask me)

/**
 * @(#)billetski.java
 *
 *
 * @author 
 * @version 1.00 2009/10/5
 */
import javax.swing.JOptionPane;	// requise pour les fenêtres de lectures-écritures
public class billetski {
        
    /**
     * Creates a new instance of <code>billetski</code>.
     */
    public billetski() {
    }
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
    	 
        //constantes
        double  PUBLICITE  = 0.18;
        double ENTRETIEN  = 0.26;
        double PROFIT   = 0.14;
        double TAXELOISIR = 3;
        double TPS        = 0.05;
        double TVQ        = 0.075;
       
        //variables
        double coutBase;
        double montantTotal;
        double montantTPS;
        double montantTVQ;
        double montantPublicite;
        double montantEntretien;
        double montantProfit;
        double pourcCoutBase;
        double pourcTPS;
        double pourcTVQ;
        double pourcPub;
        double pourcEntretien;
        double pourcTaxeLoisir;
        double pourcProfit;
        
        	
        //But du programme
         JOptionPane.showMessageDialog(
         	null, "Ce programme permet de calculer le coût de chaque parti du coût total d'un billet de ski.","But du programme",JOptionPane.INFORMATION_MESSAGE);
        coutBase = Integer.parseInt(
        	         JOptionPane.showInputDialog("Entrer le coût de base du billet."));
        	         
        montantPublicite = (coutBase*PUBLICITE);

        montantEntretien = (coutBase*ENTRETIEN);

        montantProfit =(coutBase*PROFIT);

        montantTPS = (coutBase*TPS);

        montantTVQ = (montantTPS*TVQ);

        montantTotal = ((coutBase+ montantPublicite + montantProfit + montantEntretien) + montantTPS + montantTVQ + TAXELOISIR);

        pourcCoutBase = ((coutBase/montantTotal)*100);

        pourcEntretien = ((montantEntretien/montantTotal)*100);

        pourcProfit = ((montantProfit/montantTotal)*100);

        pourcPub = ((montantPublicite/montantTotal)*100);

        pourcTaxeLoisir = ((TAXELOISIR/montantTotal)*100);
        
        pourcTPS = ((montantTPS/montantTotal)*100);
        
        pourcTVQ = ((montantTVQ/montantTotal)*100);
        
        JOptionPane.showMessageDialog(
        	null, "Cout de base:    " + coutBase + "           " + pourcCoutBase + " %" +
        	    "\nPublicité:            " + montantPublicite + "             " + pourcPub + " %" +
        	    "\nEntretien:            " + montantEntretien + "             " + pourcEntretien + " %" +
        	    "\nProfit:                   " + montantProfit + "            " + pourcProfit + " %" + 
        	    "\nTPS:                      " + montantTPS + "               " + pourcTPS + " %" +
        	    "\nTVQ:                      " + montantTVQ + "           " + pourcTVQ + " %" +
        	    "\nTaxe Loisir          " + TAXELOISIR + "               " + pourcTaxeLoisir + " %" +
        	    "\n" +
        	    "\nMontant Total:    " + montantTotal, "Coût du billet",JOptionPane.INFORMATION_MESSAGE );        
        
    }
}

I'm not sure I know exactly what you are asking.
If all you need is to round to 2 decimal places, here is an example to help you:

double d = 1.234567;
        DecimalFormat df = new DecimalFormat("#.##");
        System.out.print(df.format(d));

Yes is what I try but nothing work that say I can't because I use double ...

Can you show me an example in my own program ?

I try it

montantPublicite = (coutBase*PUBLICITE);
        DecimalFormat df = new DecimalFormat("#.##");
        System.out.print(df.format(montantPublicite));

But it show this in my general output I want to stock it in the variable montantPublicite

Any help ??? I must have finish for tomorrow :S

System.out.print( df.format(montantPublicite) );

"System.out.print" takes what is inside the parenthesis and displays it. If you want whatever is inside the parenthesis displayed somewhere else then take it and put wherever you want.