A CRY OF Help..To All Java Programmer

Question

Iam desperate please help....I Have to finish this code until tommorrow...i have done some and its running but it doesnt show the right computation...
Prob:
Mail order house sells 5 different product..prod1-$2.98, prod2-$4.50, prod3- $9.98, prod4- $4.49 and prod 5- $6.87..Write an application that reads a series of pairs of numbers as follows:
a)Product number
b)Quantity sold for one day
Program should use a switch structure to help determine the retail price for each product.Your program should calculate and display total retail value of all product sold last week. Use a TextField to obtain the product number from the user. Use sentinel -controlled loop to determine when the product should stop looping and display final results.
Note: I change temporarily the product because I am not familiar with double data types..
this is the code i have currently done..Please.please.please i need all the help..
import javax.swing.JOptionPane;
import java.text.DecimalFormat;
public class ProbMod {
     public static void main( String args[] )
          int quant,
               prodnum,
               Counter,total,input,lahatna,prodquan,
               gtotal;           
          double      
                    average;
          String
                    num1,
                    num2;
          total = 0;
          Counter = 0;
          gtotal = 1;
          input = 0;
          lahatna = 0;
          prodquan = 0;
               num1= JOptionPane.showInputDialog( "Enter Product Number, -1 to Quit");
               prodnum = Integer.parseInt(num1);
          while (prodnum != -1) {
          switch ( prodnum ) {
               case 1:
                    JOptionPane.showMessageDialog(null, "1 - $2.98");
                    break;
               case 2:
                    JOptionPane.showMessageDialog(null, "2 - $4.50");
                    break;
               case 3:
                    JOptionPane.showMessageDialog(null, "3 - $9.98");
                    break;
               case 4:
                    JOptionPane.showMessageDialog(null, "4 - $4.49");     
                    break;
               case 5:
                    JOptionPane.showMessageDialog(null, "5 - $6.87");     
                    break;
               default:
                    JOptionPane.showMessageDialog(null, "Invalid value entered" );     
                    break;
               }//end switch
               num2= JOptionPane.showInputDialog( "Enter Quantity, -1 to Quit");
               quant = Integer.parseInt(num2);
               num1= JOptionPane.showInputDialog( "Enter Product Number, -1 to Quit");
               prodnum = Integer.parseInt(num1);
               if (prodnum == 1) {
                    input = quant * 239;
               else if (prodnum == 2) {
                    input = quant * 129;     
               else if (prodnum == 3) {
                    input = quant * 99;
               else if (prodnum == 4) {
                    input = quant * 350;
               else if (prodnum == 5) {
                    input = quant * 350;
               }//endif
               gtotal = input + 0;
               Counter = Counter + 1;
          } //end while
          DecimalFormat twoDigits = new DecimalFormat( "0.00");
          if ( Counter != 0) {
          //     average = (double) total/ Counter;
               lahatna = lahatna + gtotal;
               JOptionPane.showMessageDialog(null, "Retail Total " + twoDigits.format( lahatna ),
               "Mail Order House",JOptionPane.INFORMATION_MESSAGE );
          else
          JOptionPane.showMessageDialog( null,"No Product number entered", " ",JOptionPane.INFORMATION_MESSAGE );
          System.exit( 0 );

Answer 1

Hi.
I hope the class below meets your needs. Please note that I didn't spend too much time testing it and that I cannot guarantee that it works perfectly. At least it should calculate the correct results for the input values.
public class ProbMod {
    public ProbMod() {
    public static void main(String[] args) {
        int productNumber = 0;
        int soldAmount = 0;
        double price = 0.0;
        int counter = 0;
        double total = 0.0;
        do {
            try {
                productNumber = Integer.parseInt(JOptionPane.showInputDialog("Enter product number (-1 to quit)"));
                switch( productNumber ) {
                    case -1:
                        break;
                    case 1:
                        price = 2.98;
                        break;
                    case 2:
                        price = 4.5;
                        break;
                    case 3:
                        price = 9.98;
                        break;
                    case 4:
                        price = 4.49;
                        break;
                    case 5:
                        price = 6.87;
                        break;
                    default:
                        JOptionPane.showMessageDialog(null, "You have entered an invalid product number. Please try again.");
                        throw new Exception("");
                if( productNumber != -1 ) {
                    soldAmount = Integer.parseInt(JOptionPane.showInputDialog("Enter quantity"));
                    total += (double)soldAmount * price;
                    counter++;
            } catch( NumberFormatException e1 ) {
                JOptionPane.showMessageDialog(null, "You have entered a non numeric value. Please try again.");
                productNumber = 0;
            } catch( Exception e2 ) {
                productNumber = 0;
        } while( productNumber != -1 );
        JOptionPane.showMessageDialog(null, "Retail total (" + String.valueOf(counter) + " product(s)): " + new DecimalFormat("0.00").format(total));
}Regards,
Kai