Thread: Creating Random unused ID number for every library member.

Originally Posted by clarky2006

d = d + 21;
     if (d > 30)
     {
         d= 1;
         m = m + 1;
     }
     if (m > 12)
     {
        m = 1; 
        y = y + 1;
     }

this is suppose to add 21 days

This is a second constructor, it wont compile so i had to comment out sum of the code..

    /**
     * Constructor for objects of class Loan
     */
    public Loan(int bookId, int memberId)
    {              
     int currentDay;
     int currentMonth;
     int currentYear;
     GregorianCalendar calendar = new GregorianCalendar();
     month=String.valueOf(calendar.get(GregorianCalendar.MONTH));            
     day=String.valueOf(calendar.get(GregorianCalendar.DAY_OF_MONTH));
     year=String.valueOf(calendar.get(GregorianCalendar.YEAR));
     loanDate = (day + " / " + month + " / " + year);
     //System.out.println (loanDate);
     int d = Integer.parseInt(day);
     int m = Integer.parseInt(month);
     int y = Integer.parseInt(year);
     m = m + 1; 
     loanDate = (d + " / " + m + " / " + y);
     //System.out.println ("new date - " + date);
     d = d + 21;
     if (d > 30)
     {
         d= 1;
         m = m + 1;
        }
     if (m > 12)
     {
        m = 1; 
        y = y + 1;
        }
     currentMonth = m;
     currentYear = y;
     currentDay = d;
     loanReturnDate = (currentDay + "/" + currentMonth + "/" + currentYear);
 
     this.bookId = bookId;// The book ID is initialised here.
     this.memberId = memberId;// The member's unique ID is initialised here.
     //loanDate = new GregorianCalendar();// When the loan item was taken out.
     //loanDate = new GregorianCalendar();// End of loan date.
     //loanReturnDate.add(Calendar.DATE, 21);// This adds three weeks(21 days) to the loanDate.
     //System.out.println (dateLoanDueBack);
    }

Originally Posted by Norm

Sorry, I don't understand your last post.

You should remove your code that adds 21 and use the add() method.

The last post was a second constructor. I dont know how to use the add method..

--- Update ---

The second constructor keeps highlighting new GregorianCalendar as an incompatible type..

Originally Posted by Norm

Look at how you use the get() method and the set() method.


I can't see the highlighting. Can you compile the code with javac and get the error message?

Just got my results yesterday mate...Got an A 80% all thanks to you...Cheers for all the help and support.....

Originally Posted by Norm

Glad you got it working.

Morning Norm..Not sure wot time it is across the pond..Hey got more issues with java methods
Have a look at this code please. I created this for a car dealership. here im trying to remove a car by
registration which is a "string". im not sure about using the "==" comparison. should i use ".contains" instead..?

kind regards

    public void removeCarByRegistration(String carRegistration)
    {
        Iterator<Car> it = cars.iterator();
        while(it.hasNext())
        {
            Car car = it.next();
            if(carRegistration == (car.getRegNumber()))
            {
                it.remove();
            }
        }     
    }

Originally Posted by Norm

If you want to test for equality use the equals() method.

But can I use the equals method when the return type is string?

Originally Posted by clarky2006

But can I use the equals method when the return type is string?

Here is the alternative method im thinkinking of using but not sure...

public void removeCarByRegistration(String searchString)
    {
        Iterator<Car> it = cars.iterator();
        while(it.hasNext())
        {
            Car car = it.next();
            if(car.getRegNumber().contains (searchString))
            {
                it.remove();
            }
        }     
    }

They want to be able to remove a car that is sold from the Stock Class by just entering the registration number...

Originally Posted by Norm

Does the logic work?
"AS" is contained in "ASDF"
"AS" does not equal "ASDF"

I cant really understand that last reply..What is "AS" and "ASDF"? as you know I'm new to java...

--- Update ---

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
 * Write a description of class Stock here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Stock
{
 
    // An Arraylist for storing car details.
    private ArrayList<Car> cars;
    private int carId;
 
    /**
     * Constructor for objects of class Stock
     */
    public Stock()
    {
       cars = new ArrayList<Car>();
       carId = 100;
    }
 
    /**
     * Add a new car to the Stock.
     * @param The Car to be added.
     */
    public void addCar(Car car)
    {
       cars.add(car); 
    }
 
 
    /**
     * 
     */
    public void addNewCar(String make, String model, String regNumber, double pricePaid)
    {
        carId++;// The car Id gets incremented by one in sequence when a new object is created.
        cars.add(new Car(make,  model, regNumber, carId, pricePaid));
    }
 
    public void printCarByRegistration(String searchstring)
    {
        for(Car car : cars)
        {
            if(car.getRegNumber().contains (searchstring))
            {
                car.printDetails();
            }
        }
    }
 
     public void printCarBymake(String carMake)
    {
        for(Car car : cars)
        {
            if(car.getMake() == carMake)
            {
                car.printDetails();
            }
        }
    }
 
    public void printCarByModel(String carModel)
    {
        for(Car car : cars)
        {
            if(car.getModel() == carModel)
            {
                car.printDetails();
            }
        }
    }
 
    public void removeCarByRegistration(String searchString)
    {
        Iterator<Car> it = cars.iterator();
        while(it.hasNext())
        {
            Car car = it.next();
            if(car.getRegNumber().contains (searchString))
            {
                it.remove();
            }
        }     
    }
 
 
 
}

Here is the whole code for the Stock Class...Not added the main yet...

ok..I will use the equals() method then so they have to enter the full registration for the right car to be removed instead of searchstring as searchstring would throw up the wrong cars...Thank you for the lecture this morning..You ve just taught me some proper logic...I love been educated by you..Thanks for sharing your knowledge...I would never get those if logics wrong again..Thank you once again..cheers.

Originally Posted by Norm

Cheers

Hi Norm..Just seen my tutor and hes saying that my comparison is wrong on the print carByRegistration method.
He says I should use the compareto method instead. Never used compare to before.
can you help please.

regards

/**
     * Print a car's details by its registration 
     * @param The registration of the car to be printed.
     */
    public void printCarByRegistration(String registration)
    {
        for(Car car : cars)
        {
            if(car.getRegNumber()== (registration))
            {
                car.printDetails();
            }
        }
    }