Can you help me with my program please?

Question

hi all,
I have a problem with the sellMilk function at the Milk class I don't know how to write it right I've tried everything so I need you to help me.
this function should check the expiry date of the milk and sell the required amount if it is not expired. if it was expired just delete the milkbox.
I have cases like if the first box has 5 kg and not expired , second box has 10 kg and expired, third box has 8 kg and not expired .. and if the required amount to sell is 6 kg for example it should work like this: first box should become zero because 5 kg has been sold and remainder is 1 .. so it should check the expiry date of the second box and it is expired so delete it. and then check the third box's expiry date and it is not expired so 8-1 = 7 .. and by that way 6 kg has been sold.
my program it just delete the expired box if it was the first element.
my code doesn't work well like that! here is the full program so you can check the code to help me please ..
the problem is just with SellMilk() at the Milk Class
Thank you
import java.io.*;
import java.text.*;
import java.util.*;
public class Market
    public static void main(String args[ ])
    { System.out.print("Enter the Market name: " );
        String name1 = Stdin.readLine();
        Market_Store mymarketstore = new Market_Store(name1);
   System.out.println("Welcome To " +name1+" Market ");
   System.out.println("");
        System.out.println("1-Stock new Milk");
        System.out.println("2-Stock new Milk Box");
        System.out.println("3-Sell");
        System.out.println("4- Display");
        System.out.println("");
        System.out.print("Enter your choice: ");
        int choice = Stdin.readInteger();
        while (choice != 5)
            switch (choice)
            case 1:
             mymarketstore.stockNewMilk();
                break;
            case 2:
                mymarketstore.stockMilkBox();
                break;
                case 3:
         mymarketstore.sell();
            break;
            case 4:
           mymarketstore.display();
                        break;
                        case 5:
            default:
                System.out.println("wrong Number");
                System.out.println("Enter a number between 1 to 4 ");
                System.out.println("Enter 5 to Exit");
                break;
            System.out.println("");
          System.out.println("Welcome To " +name1+" Market ");
   System.out.println("");
        System.out.println("1-Stock new Milk");
        System.out.println("2-Stock new Milk Box");
        System.out.println("3-Sell");
        System.out.println("4-Display");
        System.out.println("");
         System.out.print("Enter your choice: ");
            choice = Stdin.readInteger();
class Market_Store
        private String name;
        private Vector mymilk;
        public Market_Store(String n)
                name=n;
                mymilk = new Vector();
        public void stockNewMilk()
                String N;//milk type
                System.out.print("Enter the type of the milk: ");
                N=Stdin.readLine();
                Milk  m1 = new Milk (N);
                mymilk.addElement(m1);
        public void stockMilkBox()
        System.out.println("Milk Available in stock : ");
        for (int i=0; i<mymilk.size(); i++){
        Milk m2 = (Milk)mymilk.elementAt(i);
        System.out.print(i+1+")");
        System.out.println(m2.getMilkType());  }
                System.out.print("Enter the number of the milk to stock new box: ");
        int     ii = Stdin.readInteger();
        ((Milk)(mymilk.elementAt(ii-1))).addNewBox();
        }//end stockMilkBox
        public void sell()
                //sell specific type of milk
               System.out.println("Milk Available in stock : ");
        for (int i=0; i<mymilk.size(); i++){
        Milk m2 = (Milk)mymilk.elementAt(i);
        System.out.print(i+1+")");
        System.out.println(m2.getMilkType());
                               System.out.print("Enter the number of the milk to sell:  ");
        int     ii = Stdin.readInteger();
System.out.print("Enter the amount required in Kg:  ");
double amount = Stdin.readDouble();
        ((Milk)(mymilk.elementAt(ii-1))).sellMilk(amount);
        public void display()
        {      System.out.println("Milk Available in stock : ");
        for (int i=0; i<mymilk.size(); i++){
        Milk m2 = (Milk)mymilk.elementAt(i);
        System.out.print(i+1+")");
        System.out.println(m2.getMilkType());
                System.out.print("Enter the number of the milk to display:  ");
        int     ii = Stdin.readInteger();
                ((Milk)(mymilk.elementAt(ii-1))).display();
class MilkBox
        private Date expiredate;
        private Date date;
        private double stock;
        public MilkBox(double stck, Date ed)
                 date = new Date();
                expiredate = ed;
        public double getStock()
         return stock;     }
        public Date getDate()
                 return date;
public void setStock(double st)
{ stock = st;}
public void setExDate(Date dd)
{expiredate = dd;}
        public Date getExDate()
                 return expiredate;
  public   double sellMilkBox(double amount)
        double excessAmount = 0;
        if (amount < stock)
            double newAmount = stock - amount;
            setStock(newAmount);
        else  
            excessAmount = amount - stock;
            setStock(0);
        return excessAmount;
public     void display()
                        System.out.println("The box of "+date+" has " +stock+" KG");
class Milk
        private String Mtype;//milk type
        private Vector mybox;//vector of batches
        public Milk (String n)
                Mtype =n;
        mybox = new Vector();
  public  void addNewBox()
double stook;
System.out.print("Enter the weight of the box: ");
stook = Stdin.readDouble();
     Date exdate;//expirey date
System.out.println("Enter the expirey date of the milk box:");
       int d; int m1; int y;
          System.out.println("Enter Year:" );
          y = Stdin.readInteger();
          System.out.println("Enter Month:" );
          m1 = Stdin.readInteger();
          System.out.println("Enter Day:" );
          d = Stdin.readInteger();
               Calendar r=new GregorianCalendar(y,m1,d);
                exdate= r.getTime();
                //send the attributes to Box constructor
               MilkBox newBox = new MilkBox(stook,exdate);
                newBox.setStock(stook);
                newBox.setExDate(exdate);
                mybox.addElement(newBox);
   public void display()
                System.out.println("Milk "+Mtype);
                        for (int i=0; i<mybox.size(); i++){
                MilkBox b= (MilkBox)mybox.elementAt(i);
                b.display();
public double sellMilk (double amount)
   for(int i=0;i<mybox.size();i++)
           MilkBox b = (MilkBox)mybox.elementAt(i);
            double stock = b.sellMilkBox(amount);
            double value = b.getStock();
            Date ExpireyDate = b.getExDate();
  if ( ExpireyDate.before(new Date()))
{  mybox.removeElementAt(i);
        System.out.println("it has expired date");
if (stock >1|| value  ==  0 && ExpireyDate.after(new Date()))
{       mybox.remove(b);  
amount = stock;
if ( ExpireyDate.before(new Date()))
{  mybox.removeElementAt(i);
        System.out.println("it has expired date");
  if(amount != 0)
  System.out.println("The extra amount is "+amount+ " KG");
return amount;}
public String getMilkType()
{ return Mtype;}
//set method
void setMilkType(String n)
{ Mtype = n;}
}//end class milk
//STDIN FILE
final class Stdin
   public static BufferedReader reader=new BufferedReader
    (new InputStreamReader(System.in));
   public static String readLine()
   while(true)
   try{
       return reader.readLine();
       catch(IOException ioe)
         reportError(ioe);
       catch(NumberFormatException nfe)
        reportError(nfe);
   public static int readInteger()
    while(true)
    try{
    return Integer.parseInt(reader.readLine());
    catch(IOException ioe)
    reportError(ioe);
    catch(NumberFormatException nfe)
    reportError(nfe);
   public static double readDouble()
    while(true)
    try{
    return Double.parseDouble(reader.readLine());
    catch(IOException ioe)
    reportError(ioe);
    catch(NumberFormatException nfe)
    reportError(nfe);
    public static void reportError (Exception e)
    System.err.println("Error input:");
    System.err.println("please re-enter data");
    }Edited by: mshadows on Dec 22, 2007 12:06 AM

Answer 1

ok here is the code that has the problem .. what's wrong with it?
public double sellMilk (double amount)
   for(int i=0;i<mybox.size();i++)
           MilkBox b = (MilkBox)mybox.elementAt(i);
            double stock = b.sellMilkBox(amount);
            double value = b.getStock();
            Date ExpireyDate = b.getExDate();
  if ( ExpireyDate.before(new Date()))
{  mybox.removeElementAt(i);
        System.out.println("it has expired date");
if (stock >1|| value  ==  0 && ExpireyDate.after(new Date()))
{       mybox.remove(b);  
amount = stock;
if ( ExpireyDate.before(new Date()))
{  mybox.removeElementAt(i);
        System.out.println("it has expired date");
  if(amount != 0)
  System.out.println("The extra amount is "+amount+ " KG");
return amount;}