Help in control structure

Question

hey guys nid help on switch structure how can i place mathematical operation/ computation inside a switch without causing any problem...ive seen some switch sample but it only focuses on strings..
...you see my problem is:
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 obtaimn the product number from the user. Use sentinel -controlled loop to determine when the product should stop looping and display final results.
//Fig 4.9: Average.java
//Class average program with sentinel-controlled repetitions
import javax.swing.JOptionPane;
import java.text.DecimalFormat;
public class AverageMod {
     public static void main( String args[] )
          int quant,
               prodnum,
               gradeCounter,
               gradeValue,
               gtotal,
               total;
          double      
                    average;
          String
                    num1,
                    input;
          total = 0;
          gradeCounter = 0;
          /*input = JOptionPane.showInputDialog( "Enter Grade, -1 to Quit:");
          gradeValue = Integer.parseInt(input);
          num1= JOptionPane.showInputDialog( "Enter Product Number, -1 to Quit");
          prodnum = Integer.parseInt(num1);
          while (prodnum != -1) {
          switch ( prodnum ) {
               case 1:
               //     casetotal = casetotal + 2.98;
                    JOptionPane.showMessageDialog(null, "1 - $2.98");
                    break;
               case 2:
               //     casetotal = casetotal + 4.50;
                    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
     /*     while (prodnum != -1) {//start while*/
               total = prodnum + total ;
               gradeCounter = gradeCounter + 1;
               num1= JOptionPane.showInputDialog( "Enter Product Number, -1 to Quit");
               prodnum = Integer.parseInt(num1);
               num1= JOptionPane.showInputDialog( "Enter Quantity, -1 to Quit");
               quant = Integer.parseInt(num1);
          } //end while
          DecimalFormat twoDigits = new DecimalFormat( "0.00");
          if ( gradeCounter != 0) {
               average = (double) total/ gradeCounter;
               JOptionPane.showMessageDialog( null, "Class Average is" + twoDigits.format( average ),
               "Class Average",
               JOptionPane.INFORMATION_MESSAGE );
          else
          JOptionPane.showMessageDialog( null,"No Product number entered", "Class Average ", JOptionPane.INFORMATION_MESSAGE );
          System.exit( 0 );
i already created this code but i dont know how to make the computation..thanks GodBless

Answer 1

Can you be more specific about your problem ?
I mean what actually you are trying to do and what all inputs you are
expecting from user ?