OOP Objects and Classes help

[richlan]

Hello I am totally new to Programming, I'm in my 2nd semester and I've just started with Object Oriented Programming. As a first assignment we have been asked to create a library type system.
Here is my assignment:
Write a main function that creates some Book, Reader as well as Librarian objects and performs borrow and return operations.
We were given 3 classes Book, Address and Person (this class consisting of two subclasses: Reader and Librarian).
That look like this respectively:

public class Book {

private String title, author, publisher, ISBN;

public Book(){

}

public Book(String title, String author, String publisher, String ISBN){

}

public String getTitle() {
return title;
}

public String getAuthor() {
return author;
}

public String getPublisher() {
return publisher;
}

public String getISBN() {
return ISBN;
}

public void setTitle(String title){
this.title=title;
}

public void setAuthor(String author){
this.author=author;
}

public void setPublisher(String publisher){
this.publisher=publisher;
}

public void setISBN(String ISBN){
this.ISBN=ISBN;
}

}

If you need the other classes too, then I will post them.

I stress I am a total beginner and have but one semester of experience in Java, so please please if you understand my question don't just give me a code or tell me that it is really easy, but some sort of explanation. I have no idea how I would even think to create a book from a main function somewhere!

[sunde887]

What exactly is your question, what are you having trouble with?

[richlan]

Sorry, my exact question is how can I write a main function that creates some Book, Reader as well as Librarian objects and performs borrow and return operations?

I managed to write the classes, but I don't know how to create a main function that can use my classes to create something!

Hope that makes sense!

[sunde887]

you created all the classes?

Do you know how to create instances of a class?

Dog d = new Dog();

this does three things, creates a reference named d of type dog, creates a dog object on the heap, and links them together so d points to the newly created dog object

Now to get into main. Every class can have a main method, and when you run code it first starts running main which calls other methods or creates objects, etc.


Here is a sample

public class C{
  public static void main(String[] args){
    System.out.println("hello");
  }
}

[richlan]

Yes I created all the classes (Book, Address, Person, Reader extends Person and Librarian extends Person)! Would you like me to post them?
I'm using Eclipse, so I created all the classes on a different sheet, but they are all in the same library!

We haven't covered the instance thing in class yet, but I know how it works from reading up on the internet!

With the main thing, would I need to put that into one of my already created classes or make a new sheet and write it there using instances? Sorry for the beginner questions!

[sunde887]

I don't mind the beginner questions, I come here to help people out with what I can. As far as your question, it's really up to you where you want to create the main method, you can either make a new class that simply has a main and runs everything or slap it in an existing class. I don't need you to post the code, however; if you run into more problems, i may need to see it.